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diff --git a/docs-xml/Samba3-ByExample/SBE-2000UserNetwork.xml b/docs-xml/Samba3-ByExample/SBE-2000UserNetwork.xml new file mode 100644 index 0000000000..c86d9bcb94 --- /dev/null +++ b/docs-xml/Samba3-ByExample/SBE-2000UserNetwork.xml @@ -0,0 +1,1636 @@ +<?xml version="1.0" encoding="iso-8859-1"?> +<!DOCTYPE chapter PUBLIC "-//Samba-Team//DTD DocBook V4.2-Based Variant V1.0//EN" "http://www.samba.org/samba/DTD/samba-doc"> +<chapter id="2000users"> + <title>A Distributed 2000-User Network</title> + +<para> +There is something indeed mystical about things that are +big. Large networks exhibit a certain magnetism and exude a sense of +importance that obscures reality. You and I know that it is no more +difficult to secure a large network than it is a small one. We all +know that over and above a particular number of network clients, the +rules no longer change; the only real dynamic is the size of the domain +(much like a kingdom) over which the network ruler (oops, administrator) +has control. The real dynamic then transforms from the technical to the +political. Then again, that point is often reached well before the +kingdom (or queendom) grows large. +</para> + +<para> +If you have systematically worked your way to this chapter, hopefully you +have found some gems and techniques that are applicable in your +world. The network designs you have worked with in this book have their +strong points as well as weak ones. That is to be expected given that +they are based on real business environments, the specifics of which are +molded to serve the purposes of this book. +</para> + +<para> +This chapter is intent on wrapping up issues that are central to +implementation and design of progressively larger networks. Are you ready +for this chapter? Good, it is time to move on. +</para> + +<para> +In previous chapters, you made the assumption that your network +administration staff need detailed instruction right down to the +nuts and bolts of implementing the solution. That is still the case, +but they have graduated now. You decide to document only those issues, +methods, and techniques that are new or complex. Routine tasks such as +implementing a DNS or a DHCP server are under control. Even the basics of +Samba are largely under control. So in this section you focus on the +specifics of implementing LDAP changes, Samba changes, and approach and +design of the solution and its deployment. +</para> + +<sect1> +<title>Introduction</title> + +<para> +Abmas is a miracle company. Most businesses would have collapsed under +the weight of rapid expansion that this company has experienced. Samba +is flexible, so there is no need to reinstall the whole operating +system just because you need to implement a new network design. In fact, +you can keep an old server running right up to the moment of cutover +and then do a near-live conversion. There is no need to reinstall a +Samba server just to change the way your network should function. +</para> + +<para> +<indexterm><primary>LDAP</primary></indexterm> +Network growth is common to all organizations. In this exercise, +your preoccupation is with the mechanics of implementing Samba and +LDAP so that network users on each network segment can work +without impediment. +</para> + + <sect2> + <title>Assignment Tasks</title> + + <para> + Starting with the configuration files for the server called + <constant>MASSIVE</constant> in <link linkend="happy"/>, you now deal with the + issues that are particular to large distributed networks. Your task + is simple &smbmdash; identify the challenges, consider the + alternatives, and then design and implement a solution. + </para> + + <para> + <indexterm><primary>VPN</primary></indexterm> + Remember, you have users based in London (UK), Los Angeles, + Washington. DC, and, three buildings in New York. A significant portion + of your workforce have notebook computers and roam all over the + world. Some dial into the office, others use VPN connections over the + Internet, and others just move between buildings.i + </para> + + <para> + What do you say to an employee who normally uses a desktop + system but must spend six weeks on the road with a notebook computer? + She is concerned about email access and how to keep coworkers current + with changing documents. + </para> + + <para> + To top it all off, you have one network support person and one + help desk person based in London, a single person dedicated to all + network operations in Los Angeles, five staff for user administration + and help desk in New York, plus one <emphasis>floater</emphasis> for + Washington. + </para> + + <para> + You have outsourced all desktop deployment and management to + DirectPointe. Your concern is server maintenance and third-level + support. Build a plan and show what must be done. + </para> + + </sect2> +</sect1> + +<sect1> +<title>Dissection and Discussion</title> + +<para> +<indexterm><primary>passdb backend</primary></indexterm> +<indexterm><primary>LDAP</primary></indexterm> +In <link linkend="happy"/>, you implemented an LDAP server that provided the +<parameter>passdb backend</parameter> for the Samba servers. You +explored ways to accelerate Windows desktop profile handling and you +took control of network performance. +</para> + +<para> +<indexterm><primary>ldapsam</primary></indexterm> +<indexterm><primary>tdbsam</primary></indexterm> +<indexterm><primary>smbpasswd</primary></indexterm> +<indexterm><primary>replicated</primary></indexterm> +The implementation of an LDAP-based passdb backend (known as +<emphasis>ldapsam</emphasis> in Samba parlance), or some form of database +that can be distributed, is essential to permit the deployment of Samba +Primary and Backup Domain Controllers (PDC/BDCs). You see, the problem +is that the <emphasis>tdbsam</emphasis>-style passdb backend does not +lend itself to being replicated. The older plain-text-based +<emphasis>smbpasswd</emphasis>-style passdb backend can be replicated +using a tool such as <command>rsync</command>, but +<emphasis>smbpasswd</emphasis> suffers the drawback that it does not +support the range of account facilities demanded by modern network +managers. +</para> + +<para> +<indexterm><primary>XML</primary></indexterm> +<indexterm><primary>SQL</primary></indexterm> +The new <emphasis>tdbsam</emphasis> facility supports functionality +that is similar to an <emphasis>ldapsam</emphasis>, but the lack of +distributed infrastructure sorely limits the scope for its +deployment. This raises the following questions: Why can't I just use +an XML-based backend, or for that matter, why not use an SQL-based +backend? Is support for these tools broken? Answers to these +questions require a bit of background.</para> + +<para> +<indexterm><primary>directory</primary></indexterm> +<indexterm><primary>database</primary></indexterm> +<indexterm><primary>transaction processing</primary></indexterm> +<indexterm><primary>LDAP</primary></indexterm> +<emphasis>What is a directory?</emphasis> A directory is a +collection of information regarding objects that can be accessed to +rapidly find information that is relevant in a particular and +consistent manner. A directory differs from a database in that it is +generally more often searched (read) than updated. As a consequence, the +information is organized to facilitate read access rather than to +support transaction processing.</para> + +<para> +<indexterm><primary>Lightweight Directory Access Protocol</primary><see>LDAP</see></indexterm> +<indexterm><primary>LDAP</primary></indexterm> +<indexterm><primary>master</primary></indexterm> +<indexterm><primary>slave</primary></indexterm> +The Lightweight Directory Access Protocol (LDAP) differs +considerably from a traditional database. It has a simple search +facility that uniquely makes a highly preferred mechanism for managing +user identities. LDAP provides a scalable mechanism for distributing +the data repository and for keeping all copies (slaves) in sync with +the master repository.</para> + +<para> +<indexterm><primary>identity management</primary></indexterm> +<indexterm><primary>Active Directory</primary></indexterm> +<indexterm><primary>OpenLDAP</primary></indexterm> +Samba is a flexible and powerful file and print sharing +technology. It can use many external authentication sources and can be +part of a total authentication and identity management +infrastructure. The two most important external sources for large sites +are Microsoft Active Directory and LDAP. Sites that specifically wish to +avoid the proprietary implications of Microsoft Active Directory +naturally gravitate toward OpenLDAP.</para> + +<para> +<indexterm><primary>network</primary><secondary>routed</secondary></indexterm> +In <link linkend="happy"/>, you had to deal with a locally routed +network. All deployment concerns focused around making users happy, +and that simply means taking control over all network practices and +usage so that no one user is disadvantaged by any other. The real +lesson is one of understanding that no matter how much network +bandwidth you provide, bandwidth remains a precious resource.</para> + +<para>In this chapter, you must now consider how the overall network must +function. In particular, you must be concerned with users who move +between offices. You must take into account the way users need to +access information globally. And you must make the network robust +enough so that it can sustain partial breakdown without causing loss of +productivity.</para> + + <sect2> + <title>Technical Issues</title> + + <para> + There are at least three areas that need to be addressed as you + approach the challenge of designing a network solution for the newly + expanded business: + </para> + + <itemizedlist> + <listitem><para><indexterm><primary>mobility</primary></indexterm> + User needs such as mobility and data access</para></listitem> + + <listitem><para>The nature of Windows networking protocols</para></listitem> + + <listitem><para>Identity management infrastructure needs</para></listitem> + </itemizedlist> + + <para>Let's look at each in turn.</para> + + <sect3> + <title>User Needs</title> + + <para> + The new company has three divisions. Staff for each division are spread across + the company. Some staff are office-bound and some are mobile users. Mobile + users travel globally. Some spend considerable periods working in other offices. + Everyone wants to be able to work without constraint of productivity. + </para> + + <para> + The challenge is not insignificant. In some parts of the world, even dial-up + connectivity is poor, while in other regions political encumbrances severely + curtail user needs. Parts of the global Internet infrastructure remain shielded + off for reasons outside the scope of this discussion. + </para> + + <para> + <indexterm><primary>synchronize</primary></indexterm> + Decisions must be made regarding where data is to be stored, how it will be + replicated (if at all), and what the network bandwidth implications are. For + example, one decision that can be made is to give each office its own master + file storage area that can be synchronized to a central repository in New + York. This would permit global data to be backed up from a single location. + The synchronization tool could be <command>rsync,</command> run via a cron + job. Mobile users may use off-line file storage under Windows XP Professional. + This way, they can synchronize all files that have changed since each logon + to the network. + </para> + + <para> + <indexterm><primary>bandwidth</primary><secondary>requirements</secondary></indexterm> + <indexterm><primary>roaming profile</primary></indexterm> + No matter which way you look at this, the bandwidth requirements + for acceptable performance are substantial even if only 10 percent of + staff are global data users. A company with 3,500 employees, + 280 of whom are mobile users who use a similarly distributed + network, found they needed at least 2 Mb/sec connectivity + between the UK and US offices. Even over 2 Mb/sec bandwidth, this + company abandoned any attempt to run roaming profile usage for + mobile users. At that time, the average roaming profile took 480 + KB, while today the minimum Windows XP Professional roaming + profile involves a transfer of over 750 KB from the profile + server to and from the client. + </para> + + <para> + <indexterm><primary>wide-area</primary></indexterm> + Obviously then, user needs and wide-area practicalities dictate the economic and + technical aspects of your network design as well as for standard operating procedures. + </para> + + </sect3> + + <sect3> + <title>The Nature of Windows Networking Protocols</title> + + <para> + <indexterm><primary>profile</primary><secondary>mandatory</secondary></indexterm> + Network logons that include roaming profile handling requires from 140 KB to 2 MB. + The inclusion of support for a minimal set of common desktop applications can push + the size of a complete profile to over 15 MB. This has substantial implications + for location of user profiles. Additionally, it is a significant factor in + determining the nature and style of mandatory profiles that may be enforced as + part of a total service-level assurance program that might be implemented. + </para> + + <para> + <indexterm><primary>logon traffic</primary></indexterm> + <indexterm><primary>redirected folders</primary></indexterm> + One way to reduce the network bandwidth impact of user logon + traffic is through folder redirection. In <link linkend="happy"/>, you + implemented this in the new Windows XP Professional standard + desktop configuration. When desktop folders such as <guimenu>My + Documents</guimenu> are redirected to a network drive, they should + also be excluded from synchronization to and from the server on + logon or logout. Redirected folders are analogous to network drive + connections. + </para> + + <para><indexterm><primary>application servers</primary></indexterm> + Of course, network applications should only be run off + local application servers. As a general rule, even with 2 Mb/sec + network bandwidth, it would not make sense at all for someone who + is working out of the London office to run applications off a + server that is located in New York. + </para> + + <para> + <indexterm><primary>affordability</primary></indexterm> + When network bandwidth becomes a precious commodity (that is most + of the time), there is a significant demand to understand network + processes and to mold the limits of acceptability around the + constraints of affordability. + </para> + + <para> + When a Windows NT4/200x/XP Professional client user logs onto + the network, several important things must happen. + </para> + + <itemizedlist> + <listitem><para> + <indexterm><primary>DHCP</primary></indexterm> + The client obtains an IP address via DHCP. (DHCP is + necessary so that users can roam between offices.) + </para></listitem> + + <listitem><para> + <indexterm><primary>WINS</primary></indexterm> + <indexterm><primary>DNS</primary></indexterm> + The client must register itself with the WINS and/or DNS server. + </para></listitem> + + <listitem><para> + <indexterm><primary>Domain Controller</primary><secondary>closest</secondary></indexterm> + The client must locate the closest domain controller. + </para></listitem> + + <listitem><para> + The client must log onto a domain controller and obtain as part of + that process the location of the user's profile, load it, connect to + redirected folders, and establish all network drive and printer connections. + </para></listitem> + + <listitem><para> + The domain controller must be able to resolve the user's + credentials before the logon process is fully implemented. + </para></listitem> + </itemizedlist> + + <para> + Given that this book is about Samba and that it implements the Windows + NT4-style domain semantics, it makes little sense to compare Samba with + Microsoft Active Directory insofar as the logon protocols and principles + of operation are concerned. The following information pertains exclusively + to the interaction between a Windows XP Professional workstation and a + Samba-3.0.20 server. In the discussion that follows, use is made of DHCP and WINS. + </para> + + <para> + As soon as the Windows workstation starts up, it obtains an + IP address. This is immediately followed by registration of its + name both by broadcast and Unicast registration that is directed + at the WINS server. + </para> + + <para> + <indexterm><primary>Unicast</primary></indexterm> + <indexterm><primary>broadcast</primary><secondary>directed</secondary> + </indexterm><indexterm><primary>NetBIOS</primary></indexterm> + Given that the client is already a domain member, it then sends + a directed (Unicast) request to the WINS server seeking the list of + IP addresses for domain controllers (NetBIOS name type 0x1C). The + WINS server replies with the information requested.</para> + + <para> + <indexterm><primary>broadcast</primary><secondary>mailslot</secondary></indexterm> + <indexterm><primary>Unicast</primary></indexterm> + <indexterm><primary>WINS</primary></indexterm> + The client sends two netlogon mailslot broadcast requests + to the local network and to each of the IP addresses returned by + the WINS server. Whichever answers this request first appears to + be the machine that the Windows XP client attempts to use to + process the network logon. The mailslot messages use UDP broadcast + to the local network and UDP Unicast directed at each machine that + was listed in the WINS server response to a request for the list of + domain controllers. + </para> + + <para> + <indexterm><primary>protocol</primary><secondary>negotiation</secondary></indexterm> + <indexterm><primary>logon server</primary></indexterm> + <indexterm><primary>fail</primary></indexterm> + The logon process begins with negotiation of the SMB/CIFS + protocols that are to be used; this is followed by an exchange of + information that ultimately includes the client sending the + credentials with which the user is attempting to logon. The logon + server must now approve the further establishment of the + connection, but that is a good point to halt for now. The priority + here must center around identification of network infrastructure + needs. A secondary fact we need to know is, what happens when + local domain controllers fail or break? + </para> + + <para> + <indexterm><primary>Domain Controller</primary></indexterm> + <indexterm><primary>PDC</primary></indexterm> + <indexterm><primary>BDC</primary></indexterm> + <indexterm><primary>netlogon</primary></indexterm> + Under most circumstances, the nearest domain controller + responds to the netlogon mailslot broadcast. The exception to this + norm occurs when the nearest domain controller is too busy or is out + of service. Herein lies an important fact. This means it is + important that every network segment should have at least two + domain controllers. Since there can be only one PDC, all additional + domain controllers are by definition BDCs. + </para> + + <para> + <indexterm><primary>authentication</primary></indexterm> + <indexterm><primary>Identity Management</primary></indexterm> + The provision of sufficient servers that are BDCs is an + important design factor. The second important design factor + involves how each of the BDCs obtains user authentication + data. That is the subject of the next section, which involves key + decisions regarding Identity Management facilities. + </para> + + </sect3> + + <sect3> + <title>Identity Management Needs</title> + + <para> + <indexterm><primary>privacy</primary></indexterm> + <indexterm><primary>user credentials</primary></indexterm> + <indexterm><primary>validated</primary></indexterm> + <indexterm><primary>privileges</primary></indexterm> + Network managers recognize that in large organizations users + generally need to be given resource access based on needs, while + being excluded from other resources for reasons of privacy. It is + therefore essential that all users identify themselves at the + point of network access. The network logon is the principal means + by which user credentials are validated and filtered and appropriate + rights and privileges are allocated. + </para> + + <para> + <indexterm><primary>Identity Management</primary></indexterm> + <indexterm><primary>Yellow Pages</primary></indexterm> + <indexterm><primary>NIS</primary></indexterm> + Unfortunately, network resources tend to have their own Identity + Management facilities, the quality and manageability of which varies + from quite poor to exceptionally good. Corporations that use a mixture + of systems soon discover that until recently, few systems were + designed to interoperate. For example, UNIX systems each have an + independent user database. Sun Microsystems developed a facility that + was originally called <constant>Yellow Pages</constant>, and was renamed + when a telephone company objected to the use of its trademark. + What was once called <constant>Yellow Pages</constant> is today known + as <constant>Network Information System</constant> (NIS). + </para> + + <para> + <indexterm><primary>NIS+</primary></indexterm> + NIS gained a strong following throughout the UNIX/VMS space in a short + period of time and retained that appeal and use for over a decade. + Security concerns and inherent limitations have caused it to enter its + twilight. NIS did not gain widespread appeal outside of the UNIX world + and was not universally adopted. Sun updated this to a more secure + implementation called NIS+, but even it has fallen victim to changing + demands as the demand for directory services that can be coupled with + other information systems is catching on. + </para> + + + <para> + <indexterm><primary>NIS</primary></indexterm> + <indexterm><primary>government</primary></indexterm> + <indexterm><primary>education</primary></indexterm> + Nevertheless, both NIS and NIS+ continue to hold ground in + business areas where UNIX still has major sway. Examples of + organizations that remain firmly attached to the use of NIS and + NIS+ include large government departments, education institutions, + and large corporations that have a scientific or engineering + focus. + </para> + + <para> + <indexterm><primary>scalable</primary></indexterm> + <indexterm><primary>distributed</primary></indexterm> + Today's networking world needs a scalable, distributed Identity + Management infrastructure, commonly called a directory. The most + popular technologies today are Microsoft Active Directory service + and a number of LDAP implementations. + </para> + + <para> + <indexterm><primary>multiple directories</primary></indexterm> + The problem of managing multiple directories has become a focal + point over the past decade, creating a large market for + metadirectory products and services that allow organizations that + have multiple directories and multiple management and control + centers to provision information from one directory into + another. The attendant benefit to end users is the promise of + having to remember and deal with fewer login identities and + passwords.</para> + + <para> + <indexterm><primary>network</primary><secondary>bandwidth</secondary></indexterm> + The challenge of every large network is to find the optimum + balance of internal systems and facilities for Identity + Management resources. How well the solution is chosen and + implemented has potentially significant impact on network bandwidth + and systems response needs.</para> + + <para> + <indexterm><primary>LDAP server</primary></indexterm> + <indexterm><primary>LDAP</primary><secondary>master</secondary></indexterm> + <indexterm><primary>LDAP</primary><secondary>slave</secondary></indexterm> + In <link linkend="happy"/>, you implemented a single LDAP server for the + entire network. This may work for smaller networks, but almost + certainly fails to meet the needs of large and complex networks. The + following section documents how you may implement a single + master LDAP server with multiple slave servers.</para> + + <para> + What is the best method for implementing master/slave LDAP + servers within the context of a distributed 2,000-user network is a + question that remains to be answered.</para> + + <para> + <indexterm><primary>distributed domain</primary></indexterm> + <indexterm><primary>wide-area</primary></indexterm> + One possibility that has great appeal is to create a single, + large distributed domain. The practical implications of this + design (see <link linkend="chap7net"/>) demands the placement of + sufficient BDCs in each location. Additionally, network + administrators must make sure that profiles are not transferred + over the wide-area links, except as a totally unavoidable + measure. Network design must balance the risk of loss of user + productivity against the cost of network management and + maintenance. + </para> + + <para> + <indexterm><primary>domain name space</primary></indexterm> + The network design in <link linkend="chap7net2"/> takes the approach + that management of networks that are too remote to be managed + effectively from New York ought to be given a certain degree of + autonomy. With this rationale, the Los Angeles and London networks, + though fully integrated with those on the East Coast, each have their + own domain name space and can be independently managed and controlled. + One of the key drawbacks of this design is that it flies in the face of + the ability for network users to roam globally without some compromise + in how they may access global resources. + </para> + + <para> + <indexterm><primary>interdomain trusts</primary></indexterm> + Desk-bound users need not be negatively affected by this design, since + the use of interdomain trusts can be used to satisfy the need for global + data sharing. + </para> + + <para> + <indexterm><primary>LDAP</primary></indexterm> + <indexterm><primary>LDAP</primary><secondary>backend</secondary></indexterm> + <indexterm><primary>SID</primary></indexterm> + When Samba-3 is configured to use an LDAP backend, it stores the domain + account information in a directory entry. This account entry contains the + domain SID. An unintended but exploitable side effect is that this makes it + possible to operate with more than one PDC on a distributed network. + </para> + + <para> + <indexterm><primary>WINS</primary></indexterm> + <indexterm><primary>wins.dat</primary></indexterm> + <indexterm><primary>SID</primary></indexterm> + How might this peculiar feature be exploited? The answer is simple. It is + imperative that each network segment have its own WINS server. Major + servers on remote network segments can be given a static WINS entry in + the <filename>wins.dat</filename> file on each WINS server. This allows + all essential data to be visible from all locations. Each location would, + however, function as if it is an independent domain, while all sharing the + same domain SID. Since all domain account information can be stored in a + single LDAP backend, users have unfettered ability to roam. + </para> + + <para> + <indexterm><primary>NetBIOS name</primary><secondary>aliases</secondary></indexterm> + <indexterm><primary>fail-over</primary></indexterm> + This concept has not been exhaustively validated, though we can see no reason + why this should not work. The important facets are the following: The name of + the domain must be identical in all locations. Each network segment must have + its own WINS server. The name of the PDC must be the same in all locations; this + necessitates the use of NetBIOS name aliases for each PDC so that they can be + accessed globally using the alias and not the PDC's primary name. A single master + LDAP server can be based in New York, with multiple LDAP slave servers located + on every network segment. Finally, the BDCs should each use failover LDAP servers + that are in fact slave LDAP servers on the local segments. + </para> + + <para> + <indexterm><primary>LDAP</primary><secondary>updates</secondary></indexterm> + <indexterm><primary>domain tree</primary></indexterm> + <indexterm><primary>LDAP</primary><secondary>database</secondary></indexterm> + <indexterm><primary>LDAP</primary><secondary>directory</secondary></indexterm> + With a single master LDAP server, all network updates are effected on a single + server. In the event that this should become excessively fragile or network + bandwidth limiting, one could implement a delegated LDAP domain. This is also + known as a partitioned (or multiple partition) LDAP database and as a distributed + LDAP directory. + </para> + + <para> + As the LDAP directory grows, it becomes increasingly important + that its structure is implemented in a manner that mirrors + organizational needs, so as to limit network update and + referential traffic. It should be noted that all directory + administrators must of necessity follow the same standard + procedures for managing the directory, because retroactive correction of + inconsistent directory information can be exceedingly difficult. + </para> + + </sect3> + + </sect2> + + + <sect2> + <title>Political Issues</title> + + <para> + As organizations grow, the number of points of control increases + also. In a large distributed organization, it is important that the + Identity Management system be capable of being updated from + many locations, and it is equally important that changes made should + become usable in a reasonable period, typically + minutes rather than days (the old limitation of highly manual + systems). + </para> + + </sect2> + +</sect1> + +<sect1> + <title>Implementation</title> + + <para> + <indexterm><primary>winbind</primary></indexterm> + <indexterm><primary>LDAP</primary></indexterm> + <indexterm><primary>UID</primary></indexterm> + <indexterm><primary>GID</primary></indexterm> + Samba-3 has the ability to use multiple password (authentication and + identity resolution) backends. The diagram in <link linkend="chap7idres"/> + demonstrates how Samba uses winbind, LDAP, and NIS, the traditional system + password database. The diagram only documents the mechanisms for + authentication and identity resolution (obtaining a UNIX UID/GID) + using the specific systems shown. + </para> + + <figure id="chap7idres"> + <title>Samba and Authentication Backend Search Pathways</title> + <imagefile scale="55">chap7-idresol</imagefile> + </figure> + + <para> + <indexterm><primary>smbpasswd</primary></indexterm> + <indexterm><primary>xmlsam</primary></indexterm> + <indexterm><primary>SMB passwords</primary></indexterm> + <indexterm><primary>tdbsam</primary></indexterm> + <indexterm><primary>mysqlsam</primary></indexterm> + <indexterm><primary>LDAP</primary></indexterm> + <indexterm><primary>distributed</primary></indexterm> + Samba is capable of using the <constant>smbpasswd</constant>, + <constant>tdbsam</constant>, <constant>xmlsam</constant>, + and <constant>mysqlsam</constant> authentication databases. The SMB + passwords can, of course, also be stored in an LDAP ldapsam + backend. LDAP is the preferred passdb backend for distributed network + operations. + </para> + + <para> + <indexterm><primary>passdb backend</primary></indexterm> + Additionally, it is possible to use multiple passdb backends + concurrently as well as have multiple LDAP backends. As a result, you + can specify a failover LDAP backend. The syntax for specifying a + single LDAP backend in &smb.conf; is: +<screen> +... +passdb backend = ldapsam:ldap://master.abmas.biz +... +</screen> + This configuration tells Samba to use a single LDAP server, as shown in <link linkend="ch7singleLDAP"/>. + <figure id="ch7singleLDAP"> + <title>Samba Configuration to Use a Single LDAP Server</title> + <imagefile scale="65">ch7-singleLDAP</imagefile> + </figure> + <indexterm><primary>LDAP</primary><secondary>fail-over</secondary></indexterm> + <indexterm><primary>fail-over</primary></indexterm> + The addition of a failover LDAP server can simply be done by adding a + second entry for the failover server to the single <parameter>ldapsam</parameter> + entry, as shown here (note the particular use of the double quotes): +<screen> +... +passdb backend = ldapsam:"ldap://master.abmas.biz \ + ldap://slave.abmas.biz" +... +</screen> + This configuration tells Samba to use a master LDAP server, with failover to a slave server if necessary, + as shown in <link linkend="ch7dualLDAP"/>. + <figure id="ch7dualLDAP"> + <title>Samba Configuration to Use a Dual (Fail-over) LDAP Server</title> + <imagefile scale="65">ch7-fail-overLDAP</imagefile> + </figure> + </para> + + <para> + Some folks have tried to implement this without the use of double quotes. This is the type of entry they + created: +<screen> +... +passdb backend = ldapsam:ldap://master.abmas.biz \ + ldapsam:ldap://slave.abmas.biz +... +</screen> + <indexterm><primary>contiguous directory</primary></indexterm> + The effect of this style of entry is that Samba lists the users + that are in both LDAP databases. If both contain the same information, + it results in each record being shown twice. This is, of course, not the + solution desired for a failover implementation. The net effect of this + configuration is shown in <link linkend="ch7dualadd"/> + </para> + + <figure id="ch7dualadd"> + <title>Samba Configuration to Use Dual LDAP Databases - Broken - Do Not Use!</title> + <imagefile scale="55">ch7-dual-additive-LDAP</imagefile> + </figure> + + <para> + If, however, each LDAP database contains unique information, this may + well be an advantageous way to effectively integrate multiple LDAP databases + into one seemingly contiguous directory. Only the first database will be updated. + An example of this configuration is shown in <link linkend="ch7dualok"/>. + </para> + + <figure id="ch7dualok"> + <title>Samba Configuration to Use Two LDAP Databases - The result is additive.</title> + <imagefile scale="55">ch7-dual-additive-LDAP-Ok</imagefile> + </figure> + + <note><para> + When the use of ldapsam is specified twice, as shown here, it is imperative + that the two LDAP directories must be disjoint. If the entries are for a + master LDAP server as well as its own slave server, updates to the LDAP + database may end up being lost or corrupted. You may safely use multiple + LDAP backends only if both are entirely separate from each other. + </para></note> + + <para> + It is assumed that the network you are working with follows in a + pattern similar to what was covered in <link linkend="happy"/>. The following steps + permit the operation of a master/slave OpenLDAP arrangement. + </para> + + <procedure> + <title>Implementation Steps for an LDAP Slave Server</title> + + <step><para> + <indexterm><primary>SUSE Linux</primary></indexterm> + <indexterm><primary>Red Hat Linux</primary></indexterm> + Log onto the master LDAP server as <constant>root</constant>. + You are about to change the configuration of the LDAP server, so it + makes sense to temporarily halt it. Stop OpenLDAP from running on + SUSE Linux by executing: +<screen> +&rootprompt; rcldap stop +</screen> + On Red Hat Linux, you can do this by executing: +<screen> +&rootprompt; service ldap stop +</screen> + </para></step> + + <step><para> + <indexterm><primary>/etc/openldap/slapd.conf</primary></indexterm> + Edit the <filename>/etc/openldap/slapd.conf</filename> file so it + matches the content of <link linkend="ch7-LDAP-master"/>. + </para></step> + + <step><para> + Create a file called <filename>admin-accts.ldif</filename> with the following contents: +<screen> +dn: cn=updateuser,dc=abmas,dc=biz +objectClass: person +cn: updateuser +sn: updateuser +userPassword: not24get + +dn: cn=sambaadmin,dc=abmas,dc=biz +objectClass: person +cn: sambaadmin +sn: sambaadmin +userPassword: buttercup +</screen> + </para></step> + + <step><para> + Add an account called <quote>updateuser</quote> to the master LDAP server as shown here: +<screen> +&rootprompt; slapadd -v -l admin-accts.ldif +</screen> + </para></step> + + <step><para> + <indexterm><primary>LDIF</primary></indexterm> + <indexterm><primary>LDAP</primary><secondary>preload</secondary></indexterm> + Change directory to a suitable place to dump the contents of the + LDAP server. The dump file (and LDIF file) is used to preload + the slave LDAP server database. You can dump the database by executing: +<screen> +&rootprompt; slapcat -v -l LDAP-transfer-LDIF.txt +</screen> + Each record is written to the file. + </para></step> + + <step><para> + <indexterm><primary>LDAP-transfer-LDIF.txt</primary></indexterm> + Copy the file <filename>LDAP-transfer-LDIF.txt</filename> to the intended + slave LDAP server. A good location could be in the directory + <filename>/etc/openldap/preload</filename>. + </para></step> + + <step><para> + Log onto the slave LDAP server as <constant>root</constant>. You can + now configure this server so the <filename>/etc/openldap/slapd.conf</filename> + file matches the content of <link linkend="ch7-LDAP-slave"/>. + </para></step> + + <step><para> + Change directory to the location in which you stored the + <filename>LDAP-transfer-LDIF.txt</filename> file (<filename>/etc/openldap/preload</filename>). + While in this directory, execute: +<screen> +&rootprompt; slapadd -v -l LDAP-transfer-LDIF.txt +</screen> + If all goes well, the following output confirms that the data is being loaded + as intended: +<screen> +added: "dc=abmas,dc=biz" (00000001) +added: "cn=sambaadmin,dc=abmas,dc=biz" (00000002) +added: "cn=updateuser,dc=abmas,dc=biz" (00000003) +added: "ou=People,dc=abmas,dc=biz" (00000004) +added: "ou=Groups,dc=abmas,dc=biz" (00000005) +added: "ou=Computers,dc=abmas,dc=biz" (00000006) +added: "uid=Administrator,ou=People,dc=abmas,dc=biz" (00000007) +added: "uid=nobody,ou=People,dc=abmas,dc=biz" (00000008) +added: "cn=Domain Admins,ou=Groups,dc=abmas,dc=biz" (00000009) +added: "cn=Domain Users,ou=Groups,dc=abmas,dc=biz" (0000000a) +added: "cn=Domain Guests,ou=Groups,dc=abmas,dc=biz" (0000000b) +added: "uid=bobj,ou=People,dc=abmas,dc=biz" (0000000c) +added: "sambaDomainName=MEGANET2,dc=abmas,dc=biz" (0000000d) +added: "uid=stans,ou=People,dc=abmas,dc=biz" (0000000e) +added: "uid=chrisr,ou=People,dc=abmas,dc=biz" (0000000f) +added: "uid=maryv,ou=People,dc=abmas,dc=biz" (00000010) +added: "cn=Accounts,ou=Groups,dc=abmas,dc=biz" (00000011) +added: "cn=Finances,ou=Groups,dc=abmas,dc=biz" (00000012) +added: "cn=PIOps,ou=Groups,dc=abmas,dc=biz" (00000013) +</screen> + </para></step> + + <step><para> + Now start the LDAP server and set it to run automatically on system reboot by executing: +<screen> +&rootprompt; rcldap start +&rootprompt; chkconfig ldap on +</screen> + On Red Hat Linux, execute the following: +<screen> +&rootprompt; service ldap start +&rootprompt; chkconfig ldap on +</screen> + </para></step> + + <step><para> + <indexterm><primary>chkconfig</primary></indexterm> + <indexterm><primary>service</primary></indexterm> + <indexterm><primary>rcldap</primary></indexterm> + Go back to the master LDAP server. Execute the following to start LDAP as well + as <command>slurpd</command>, the synchronization daemon, as shown here: +<screen> +&rootprompt; rcldap start +&rootprompt; chkconfig ldap on +&rootprompt; rcslurpd start +&rootprompt; chkconfig slurpd on +</screen> + <indexterm><primary>slurpd</primary></indexterm> + On Red Hat Linux, check the equivalent command to start <command>slurpd</command>. + </para></step> + + <step><para> + <indexterm><primary>smbldap-useradd</primary></indexterm> + On the master LDAP server you may now add an account to validate that replication + is working. Assuming the configuration shown in <link linkend="happy"/>, execute: +<screen> +&rootprompt; /var/lib/samba/sbin/smbldap-useradd -a fruitloop +</screen> + </para></step> + + <step><para> + On the slave LDAP server, change to the directory <filename>/var/lib/ldap</filename>. + There should now be a file called <filename>replogfile</filename>. If replication worked + as expected, the content of this file should be: +<screen> +time: 1072486403 +dn: uid=fruitloop,ou=People,dc=abmas,dc=biz +changetype: modify +replace: sambaProfilePath +sambaProfilePath: \\MASSIVE\profiles\fruitloop +- +replace: sambaHomePath +sambaHomePath: \\MASSIVE\homes +- +replace: entryCSN +entryCSN: 2003122700:43:38Z#0x0005#0#0000 +- +replace: modifiersName +modifiersName: cn=Manager,dc=abmas,dc=biz +- +replace: modifyTimestamp +modifyTimestamp: 20031227004338Z +- +</screen> + </para></step> + + <step><para> + Given that this first slave LDAP server is now working correctly, you may now + implement additional slave LDAP servers as required. + </para></step> + + <step><para> + On each machine (PDC and BDCs) after the respective &smb.conf; files have been created as shown in + <link linkend="ch7-massmbconfA">Primary Domain Controller &smb.conf; File &smbmdash; Part A + B + C</link> and + on BDCs the <link linkend="ch7-slvsmbocnfA">Backup Domain Controller &smb.conf; File &smbmdash; Part A + + B + C</link> execute the following: +<screen> +&rootprompt; smbpasswd -w buttercup +</screen> + This will install in the <filename>secrets.tdb</filename> file the password that Samba will need to + manage (write to) the LDAP Master server to perform account updates. + </para></step> + + </procedure> + +<example id="ch7-LDAP-master"> +<title>LDAP Master Server Configuration File &smbmdash; <filename>/etc/openldap/slapd.conf</filename></title> +<screen> +include /etc/openldap/schema/core.schema +include /etc/openldap/schema/cosine.schema +include /etc/openldap/schema/inetorgperson.schema +include /etc/openldap/schema/nis.schema +include /etc/openldap/schema/samba.schema + +pidfile /var/run/slapd/slapd.pid +argsfile /var/run/slapd/slapd.args + +database bdb +suffix "dc=abmas,dc=biz" +rootdn "cn=Manager,dc=abmas,dc=biz" + +# rootpw = not24get +rootpw {SSHA}86kTavd9Dw3FAz6qzWTrCOKX/c0Qe+UV + +replica host=lapdc.abmas.biz:389 + suffix="dc=abmas,dc=biz" + binddn="cn=updateuser,dc=abmas,dc=biz" + bindmethod=simple credentials=not24get + +access to attrs=sambaLMPassword,sambaNTPassword + by dn="cn=sambaadmin,dc=abmas,dc=biz" write + by * none + +replogfile /var/lib/ldap/replogfile + +directory /var/lib/ldap + +# Indices to maintain +index objectClass eq +index cn pres,sub,eq +index sn pres,sub,eq +index uid pres,sub,eq +index displayName pres,sub,eq +index uidNumber eq +index gidNumber eq +index memberUID eq +index sambaSID eq +index sambaPrimaryGroupSID eq +index sambaDomainName eq +index default sub +</screen> +</example> + +<example id="ch7-LDAP-slave"> +<title>LDAP Slave Configuration File &smbmdash; <filename>/etc/openldap/slapd.conf</filename></title> +<screen> +include /etc/openldap/schema/core.schema +include /etc/openldap/schema/cosine.schema +include /etc/openldap/schema/inetorgperson.schema +include /etc/openldap/schema/nis.schema +include /etc/openldap/schema/samba.schema + +pidfile /var/run/slapd/slapd.pid +argsfile /var/run/slapd/slapd.args + +database bdb +suffix "dc=abmas,dc=biz" +rootdn "cn=Manager,dc=abmas,dc=biz" + +# rootpw = not24get +rootpw {SSHA}86kTavd9Dw3FAz6qzWTrCOKX/c0Qe+UV + +access to * + by dn=cn=updateuser,dc=abmas,dc=biz write + by * read + +updatedn cn=updateuser,dc=abmas,dc=biz +updateref ldap://massive.abmas.biz + +directory /var/lib/ldap + +# Indices to maintain +index objectClass eq +index cn pres,sub,eq +index sn pres,sub,eq +index uid pres,sub,eq +index displayName pres,sub,eq +index uidNumber eq +index gidNumber eq +index memberUID eq +index sambaSID eq +index sambaPrimaryGroupSID eq +index sambaDomainName eq +index default sub +</screen> +</example> + +<example id="ch7-massmbconfA"> +<title>Primary Domain Controller &smb.conf; File &smbmdash; Part A</title> +<smbconfblock> +<smbconfcomment>Global parameters</smbconfcomment> +<smbconfsection name="[global]"/> +<smbconfoption name="unix charset">LOCALE</smbconfoption> +<smbconfoption name="workgroup">MEGANET2</smbconfoption> +<smbconfoption name="passdb backend">ldapsam:ldap://massive.abmas.biz</smbconfoption> +<smbconfoption name="username map">/etc/samba/smbusers</smbconfoption> +<smbconfoption name="log level">1</smbconfoption> +<smbconfoption name="syslog">0</smbconfoption> +<smbconfoption name="log file">/var/log/samba/%m</smbconfoption> +<smbconfoption name="max log size">0</smbconfoption> +<smbconfoption name="smb ports">139</smbconfoption> +<smbconfoption name="name resolve order">wins bcast hosts</smbconfoption> +<smbconfoption name="time server">Yes</smbconfoption> +<smbconfoption name="printcap name">CUPS</smbconfoption> +<smbconfoption name="add user script">/opt/IDEALX/sbin/smbldap-useradd -m '%u'</smbconfoption> +<smbconfoption name="delete user script">/opt/IDEALX/sbin/smbldap-userdel '%u'</smbconfoption> +<smbconfoption name="add group script">/opt/IDEALX/sbin/smbldap-groupadd -p '%g'</smbconfoption> +<smbconfoption name="delete group script">/opt/IDEALX/sbin/smbldap-groupdel '%g'</smbconfoption> +<smbconfoption name="add user to group script">/opt/IDEALX/sbin/smbldap-groupmod -m '%g' '%u'</smbconfoption> +<smbconfoption name="delete user from group script">/opt/IDEALX/sbin/smbldap-groupmod -x '%g' '%u'</smbconfoption> +<smbconfoption name="set primary group script">/opt/IDEALX/sbin/smbldap-usermod -g '%g' '%u'</smbconfoption> +<smbconfoption name="add machine script">/opt/IDEALX/sbin/smbldap-useradd -w '%u'</smbconfoption> +<smbconfoption name="shutdown script">/var/lib/samba/scripts/shutdown.sh</smbconfoption> +<smbconfoption name="abort shutdown script">/sbin/shutdown -c</smbconfoption> +<smbconfoption name="logon script">scripts\logon.bat</smbconfoption> +<smbconfoption name="logon path">\\%L\profiles\%U</smbconfoption> +<smbconfoption name="logon drive">X:</smbconfoption> +<smbconfoption name="domain logons">Yes</smbconfoption> +<smbconfoption name="domain master">Yes</smbconfoption> +<smbconfoption name="wins support">Yes</smbconfoption> +<smbconfoption name="ldap suffix">dc=abmas,dc=biz</smbconfoption> +<smbconfoption name="ldap machine suffix">ou=People</smbconfoption> +<smbconfoption name="ldap user suffix">ou=People</smbconfoption> +<smbconfoption name="ldap group suffix">ou=Groups</smbconfoption> +<smbconfoption name="ldap idmap suffix">ou=Idmap</smbconfoption> +<smbconfoption name="ldap admin dn">cn=sambaadmin,dc=abmas,dc=biz</smbconfoption> +<smbconfoption name="idmap backend">ldap://massive.abmas.biz</smbconfoption> +<smbconfoption name="idmap uid">10000-20000</smbconfoption> +<smbconfoption name="idmap gid">10000-20000</smbconfoption> +<smbconfoption name="printer admin">root</smbconfoption> +<smbconfoption name="printing">cups</smbconfoption> +</smbconfblock> +</example> + +<example id="ch7-massmbconfB"> +<title>Primary Domain Controller &smb.conf; File &smbmdash; Part B</title> +<smbconfblock> +<smbconfsection name="[IPC$]"/> +<smbconfoption name="path">/tmp</smbconfoption> + +<smbconfsection name="[accounts]"/> +<smbconfoption name="comment">Accounting Files</smbconfoption> +<smbconfoption name="path">/data/accounts</smbconfoption> +<smbconfoption name="read only">No</smbconfoption> + +<smbconfsection name="[service]"/> +<smbconfoption name="comment">Financial Services Files</smbconfoption> +<smbconfoption name="path">/data/service</smbconfoption> +<smbconfoption name="read only">No</smbconfoption> + +<smbconfsection name="[pidata]"/> +<smbconfoption name="comment">Property Insurance Files</smbconfoption> +<smbconfoption name="path">/data/pidata</smbconfoption> +<smbconfoption name="read only">No</smbconfoption> + +<smbconfsection name="[homes]"/> +<smbconfoption name="comment">Home Directories</smbconfoption> +<smbconfoption name="valid users">%S</smbconfoption> +<smbconfoption name="read only">No</smbconfoption> +<smbconfoption name="browseable">No</smbconfoption> + +<smbconfsection name="[printers]"/> +<smbconfoption name="comment">SMB Print Spool</smbconfoption> +<smbconfoption name="path">/var/spool/samba</smbconfoption> +<smbconfoption name="guest ok">Yes</smbconfoption> +<smbconfoption name="printable">Yes</smbconfoption> +<smbconfoption name="browseable">No</smbconfoption> +</smbconfblock> +</example> + +<example id="ch7-massmbconfC"> +<title>Primary Domain Controller &smb.conf; File &smbmdash; Part C</title> +<smbconfblock> +<smbconfsection name="[apps]"/> +<smbconfoption name="comment">Application Files</smbconfoption> +<smbconfoption name="path">/apps</smbconfoption> +<smbconfoption name="admin users">bjones</smbconfoption> +<smbconfoption name="read only">No</smbconfoption> + +<smbconfsection name="[netlogon]"/> +<smbconfoption name="comment">Network Logon Service</smbconfoption> +<smbconfoption name="path">/var/lib/samba/netlogon</smbconfoption> +<smbconfoption name="admin users">root, Administrator</smbconfoption> +<smbconfoption name="guest ok">Yes</smbconfoption> +<smbconfoption name="locking">No</smbconfoption> + +<smbconfsection name="[profiles]"/> +<smbconfoption name="comment">Profile Share</smbconfoption> +<smbconfoption name="path">/var/lib/samba/profiles</smbconfoption> +<smbconfoption name="read only">No</smbconfoption> +<smbconfoption name="profile acls">Yes</smbconfoption> + +<smbconfsection name="[profdata]"/> +<smbconfoption name="comment">Profile Data Share</smbconfoption> +<smbconfoption name="path">/var/lib/samba/profdata</smbconfoption> +<smbconfoption name="read only">No</smbconfoption> +<smbconfoption name="profile acls">Yes</smbconfoption> + +<smbconfsection name="[print$]"/> +<smbconfoption name="comment">Printer Drivers</smbconfoption> +<smbconfoption name="path">/var/lib/samba/drivers</smbconfoption> +<smbconfoption name="write list">root</smbconfoption> +<smbconfoption name="admin users">root, Administrator</smbconfoption> +</smbconfblock> +</example> + +<example id="ch7-slvsmbocnfA"> +<title>Backup Domain Controller &smb.conf; File &smbmdash; Part A</title> +<smbconfblock> +<smbconfcomment># Global parameters</smbconfcomment> +<smbconfsection name="[global]"/> +<smbconfoption name="unix charset">LOCALE</smbconfoption> +<smbconfoption name="workgroup">MEGANET2</smbconfoption> +<smbconfoption name="netbios name">BLDG1</smbconfoption> +<smbconfoption name="passdb backend">ldapsam:ldap://lapdc.abmas.biz</smbconfoption> +<smbconfoption name="username map">/etc/samba/smbusers</smbconfoption> +<smbconfoption name="log level">1</smbconfoption> +<smbconfoption name="syslog">0</smbconfoption> +<smbconfoption name="log file">/var/log/samba/%m</smbconfoption> +<smbconfoption name="max log size">50</smbconfoption> +<smbconfoption name="smb ports">139</smbconfoption> +<smbconfoption name="name resolve order">wins bcast hosts</smbconfoption> +<smbconfoption name="printcap name">CUPS</smbconfoption> +<smbconfoption name="show add printer wizard">No</smbconfoption> +<smbconfoption name="logon script">scripts\logon.bat</smbconfoption> +<smbconfoption name="logon path">\\%L\profiles\%U</smbconfoption> +<smbconfoption name="logon drive">X:</smbconfoption> +<smbconfoption name="domain logons">Yes</smbconfoption> +<smbconfoption name="os level">63</smbconfoption> +<smbconfoption name="domain master">No</smbconfoption> +<smbconfoption name="wins server">192.168.2.1</smbconfoption> +<smbconfoption name="ldap suffix">dc=abmas,dc=biz</smbconfoption> +<smbconfoption name="ldap machine suffix">ou=People</smbconfoption> +<smbconfoption name="ldap user suffix">ou=People</smbconfoption> +<smbconfoption name="ldap group suffix">ou=Groups</smbconfoption> +<smbconfoption name="ldap idmap suffix">ou=Idmap</smbconfoption> +<smbconfoption name="ldap admin dn">cn=sambaadmin,dc=abmas,dc=biz</smbconfoption> +<smbconfoption name="utmp">Yes</smbconfoption> +<smbconfoption name="idmap backend">ldap://massive.abmas.biz</smbconfoption> +<smbconfoption name="idmap uid">10000-20000</smbconfoption> +<smbconfoption name="idmap gid">10000-20000</smbconfoption> +<smbconfoption name="printing">cups</smbconfoption> + +<smbconfsection name="[accounts]"/> +<smbconfoption name="comment">Accounting Files</smbconfoption> +<smbconfoption name="path">/data/accounts</smbconfoption> +<smbconfoption name="read only">No</smbconfoption> + +<smbconfsection name="[service]"/> +<smbconfoption name="comment">Financial Services Files</smbconfoption> +<smbconfoption name="path">/data/service</smbconfoption> +<smbconfoption name="read only">No</smbconfoption> +</smbconfblock> +</example> + +<example id="ch7-slvsmbocnfB"> +<title>Backup Domain Controller &smb.conf; File &smbmdash; Part B</title> +<smbconfblock> +<smbconfsection name="[pidata]"/> +<smbconfoption name="comment">Property Insurance Files</smbconfoption> +<smbconfoption name="path">/data/pidata</smbconfoption> +<smbconfoption name="read only">No</smbconfoption> + +<smbconfsection name="[homes]"/> +<smbconfoption name="comment">Home Directories</smbconfoption> +<smbconfoption name="valid users">%S</smbconfoption> +<smbconfoption name="read only">No</smbconfoption> +<smbconfoption name="browseable">No</smbconfoption> + +<smbconfsection name="[printers]"/> +<smbconfoption name="comment">SMB Print Spool</smbconfoption> +<smbconfoption name="path">/var/spool/samba</smbconfoption> +<smbconfoption name="guest ok">Yes</smbconfoption> +<smbconfoption name="printable">Yes</smbconfoption> +<smbconfoption name="browseable">No</smbconfoption> + +<smbconfsection name="[apps]"/> +<smbconfoption name="comment">Application Files</smbconfoption> +<smbconfoption name="path">/apps</smbconfoption> +<smbconfoption name="admin users">bjones</smbconfoption> +<smbconfoption name="read only">No</smbconfoption> + +<smbconfsection name="[netlogon]"/> +<smbconfoption name="comment">Network Logon Service</smbconfoption> +<smbconfoption name="path">/var/lib/samba/netlogon</smbconfoption> +<smbconfoption name="guest ok">Yes</smbconfoption> +<smbconfoption name="locking">No</smbconfoption> + +<smbconfsection name="[profiles]"/> +<smbconfoption name="comment">Profile Share</smbconfoption> +<smbconfoption name="path">/var/lib/samba/profiles</smbconfoption> +<smbconfoption name="read only">No</smbconfoption> +<smbconfoption name="profile acls">Yes</smbconfoption> + +<smbconfsection name="[profdata]"/> +<smbconfoption name="comment">Profile Data Share</smbconfoption> +<smbconfoption name="path">/var/lib/samba/profdata</smbconfoption> +<smbconfoption name="read only">No</smbconfoption> +<smbconfoption name="profile acls">Yes</smbconfoption> +</smbconfblock> +</example> + + <sect2> + <title>Key Points Learned</title> + + <itemizedlist> + <listitem><para> + <indexterm><primary>LDAP</primary></indexterm><indexterm><primary>BDC</primary></indexterm> + Where Samba-3 is used as a domain controller, the use of LDAP is an + essential component to permit the use of BDCs. + </para></listitem> + + <listitem><para> + <indexterm><primary>wide-area</primary></indexterm> + Replication of the LDAP master server to create a network of BDCs + is an important mechanism for limiting WAN traffic. + </para></listitem> + + <listitem><para> + Network administration presents many complex challenges, most of which + can be satisfied by good design but that also require sound communication + and unification of management practices. This can be highly challenging in + a large, globally distributed network. + </para></listitem> + + <listitem><para> + Roaming profiles must be contained to the local network segment. Any + departure from this may clog wide-area arteries and slow legitimate network + traffic to a crawl. + </para></listitem> + </itemizedlist> + + </sect2> + + <figure id="chap7net"> + <title>Network Topology &smbmdash; 2000 User Complex Design A</title> + <imagefile scale="80">chap7-net-Ar</imagefile> + </figure> + + <figure id="chap7net2"> + <title>Network Topology &smbmdash; 2000 User Complex Design B</title> + <imagefile scale="80">chap7-net2-Br</imagefile> + </figure> + +</sect1> + +<sect1> + <title>Questions and Answers</title> + + <para> + There is much rumor and misinformation regarding the use of MS Windows networking protocols. + These questions are just a few of those frequently asked. + </para> + + <qandaset defaultlabel="chap07qa" type="number"> + <qandaentry> + <question> + + <para> + <indexterm><primary>DHCP</primary></indexterm> + <indexterm><primary>network</primary><secondary>bandwidth</secondary></indexterm> + Is it true that DHCP uses lots of WAN bandwidth? + </para> + + </question> + <answer> + + <para> + <indexterm><primary>DHCP</primary><secondary>Relay Agent</secondary></indexterm> + <indexterm><primary>routers</primary></indexterm> + <indexterm><primary>DHCP</primary><secondary>servers</secondary></indexterm> + It is a smart practice to localize DHCP servers on each network segment. As a + rule, there should be two DHCP servers per network segment. This means that if + one server fails, there is always another to service user needs. DHCP requests use + only UDP broadcast protocols. It is possible to run a DHCP Relay Agent on network + routers. This makes it possible to run fewer DHCP servers. + </para> + + <para> + <indexterm><primary>DHCP</primary><secondary>request</secondary></indexterm> + <indexterm><primary>DHCP</primary><secondary>traffic</secondary></indexterm> + A DHCP network address request and confirmation usually results in about six UDP packets. + The packets are from 60 to 568 bytes in length. Let us consider a site that has 300 DHCP + clients and that uses a 24-hour IP address lease. This means that all clients renew + their IP address lease every 24 hours. If we assume an average packet length equal to the + maximum (just to be on the safe side), and we have a 128 Kb/sec wide-area connection, + how significant would the DHCP traffic be if all of it were to use DHCP Relay? + </para> + + <para> + I must stress that this is a bad design, but here is the calculation: +<screen> +Daily Network Capacity: 128,000 (Kbits/s) / 8 (bits/byte) + x 3600 (sec/hr) x 24 (hrs/day)= 2288 Mbytes/day. + +DHCP traffic: 300 (clients) x 6 (packets) + x 512 (bytes/packet) = 0.9 Mbytes/day. +</screen> + From this can be seen that the traffic impact would be minimal. + </para> + + <para> + <indexterm><primary>DNS</primary><secondary>Dynamic</secondary></indexterm> + <indexterm><primary>DHCP</primary></indexterm> + Even when DHCP is configured to do DNS update (dynamic DNS) over a wide-area link, + the impact of the update is no more than the DHCP IP address renewal traffic and thus + still insignificant for most practical purposes. + </para> + + </answer> + </qandaentry> + + <qandaentry> + <question> + + <para> + <indexterm><primary>background communication</primary></indexterm> + <indexterm><primary>LDAP</primary><secondary>master/slave</secondary><tertiary>background communication</tertiary></indexterm> + How much background communication takes place between a master LDAP server and its slave LDAP servers? + </para> + + </question> + <answer> + + <para> + <indexterm><primary>slurpd</primary></indexterm> + The process that controls the replication of data from the master LDAP server to the slave LDAP + servers is called <command>slurpd</command>. The <command>slurpd</command> remains nascent (quiet) + until an update must be propagated. The propagation traffic per LDAP slave to update (add/modify/delete) + two user accounts requires less than 10KB traffic. + </para> + + </answer> + </qandaentry> + + <qandaentry> + <question> + + <para> + LDAP has a database. Is LDAP not just a fancy database front end? + </para> + + </question> + <answer> + + <para> + <indexterm><primary>database</primary></indexterm> + <indexterm><primary>LDAP</primary><secondary>database</secondary></indexterm> + <indexterm><primary>SQL</primary></indexterm> + <indexterm><primary>transactional</primary></indexterm> + LDAP does store its data in a database of sorts. In fact, the LDAP backend is an application-specific + data storage system. This type of database is indexed so that records can be rapidly located, but the + database is not generic and can be used only in particular pre-programmed ways. General external + applications do not gain access to the data. This type of database is used also by SQL servers. Both + an SQL server and an LDAP server provide ways to access the data. An SQL server has a transactional + orientation and typically allows external programs to perform ad hoc queries, even across data tables. + An LDAP front end is a purpose-built tool that has a search orientation that is designed around specific + simple queries. The term <constant>database</constant> is heavily overloaded and thus much misunderstood. + </para> + + </answer> + </qandaentry> + + <qandaentry> + <question> + + <para> + <indexterm><primary>OpenLDAP</primary></indexterm> + Can Active Directory obtain account information from an OpenLDAP server? + </para> + + </question> + <answer> + + <para> + <indexterm><primary>meta-directory</primary></indexterm> + No, at least not directly. It is possible to provision Active Directory from and/or to an OpenLDAP + database through use of a metadirectory server. Microsoft MMS (now called MIIS) can interface + to OpenLDAP using standard LDAP queries and updates. + </para> + + </answer> + </qandaentry> + + <qandaentry> + <question> + + <para> + What are the parts of a roaming profile? How large is each part? + </para> + + </question> + <answer> + + <para><indexterm> + <primary>roaming profile</primary> + </indexterm> + A roaming profile consists of + </para> + + <itemizedlist> + <listitem><para> + Desktop folders such as <constant>Desktop</constant>, <constant>My Documents</constant>, + <constant>My Pictures</constant>, <constant>My Music</constant>, <constant>Internet Files</constant>, + <constant>Cookies</constant>, <constant>Application Data</constant>, + <constant>Local Settings,</constant> and more. See <link linkend="happy"/>, <link linkend="XP-screen001"/>. + </para> + + <para> + <indexterm><primary>folder redirection</primary></indexterm> + Each of these can be anywhere from a few bytes to gigabytes in capacity. Fortunately, all + such folders can be redirected to network drive resources. See <link linkend="redirfold"/> + for more information regarding folder redirection. + </para></listitem> + + <listitem><para> + A static or rewritable portion that is typically only a few files (2-5 KB of information). + </para></listitem> + + <listitem><para> + <indexterm><primary>NTUSER.DAT</primary></indexterm> + <indexterm><primary>HKEY_LOCAL_USER</primary></indexterm> + The registry load file that modifies the <constant>HKEY_LOCAL_USER</constant> hive. This is + the <filename>NTUSER.DAT</filename> file. It can be from 0.4 to 1.5 MB. + </para></listitem> + </itemizedlist> + + <para> + <indexterm><primary>Microsoft Outlook</primary><secondary>PST files</secondary></indexterm> + Microsoft Outlook PST files may be stored in the <constant>Local Settings\Application Data</constant> + folder. It can be up to 2 GB in size per PST file. + </para> + + </answer> + </qandaentry> + + <qandaentry> + <question> + + <para> + Can the <constant>My Documents</constant> folder be stored on a network drive? + </para> + + </question> + <answer> + + <para> + <indexterm><primary>UNC name</primary></indexterm> + <indexterm><primary>Universal Naming Convention</primary><see>UNC name</see></indexterm> + Yes. More correctly, such folders can be redirected to network shares. No specific network drive + connection is required. Registry settings permit this to be redirected directly to a UNC (Universal + Naming Convention) resource, though it is possible to specify a network drive letter instead of a + UNC name. See <link linkend="redirfold"/>. + </para> + + </answer> + </qandaentry> + + <qandaentry> + <question> + + <para> + <indexterm><primary>wide-area</primary></indexterm> + <indexterm><primary>network</primary><secondary>bandwidth</secondary></indexterm> + <indexterm><primary>WINS</primary></indexterm> + How much WAN bandwidth does WINS consume? + </para> + + </question> + <answer> + + <para> + <indexterm><primary>NetBIOS</primary><secondary>name cache</secondary></indexterm> + <indexterm><primary>WINS server</primary></indexterm> + <indexterm><primary>domain replication</primary></indexterm> + MS Windows clients cache information obtained from WINS lookups in a local NetBIOS name cache. + This keeps WINS lookups to a minimum. On a network with 3500 MS Windows clients and a central WINS + server, the total bandwidth demand measured at the WINS server, averaged over an 8-hour working day, + was less than 30 KB/sec. Analysis of network traffic over a 6-week period showed that the total + of all background traffic consumed about 11 percent of available bandwidth over 64 Kb/sec links. + Background traffic consisted of domain replication, WINS queries, DNS lookups, and authentication + traffic. Each of 11 branch offices had a 64 Kb/sec wide-area link, with a 1.5 Mb/sec main connection + that aggregated the branch office connections plus an Internet connection. + </para> + + <para> + In conclusion, the total load afforded through WINS traffic is again marginal to total operational + usage &smbmdash; as it should be. + </para> + + </answer> + </qandaentry> + + <qandaentry> + <question> + + <para> + How many BDCs should I have? What is the right number of Windows clients per server? + </para> + + </question> + <answer> + + <para> + It is recommended to have at least one BDC per network segment, including the segment served + by the PDC. Actual requirements vary depending on the working load on each of the BDCs and the + load demand pattern of client usage. I have seen sites that function without problem with 200 + clients served by one BDC, and yet other sites that had one BDC per 20 clients. In one particular + company, there was a drafting office that had 30 CAD/CAM operators served by one server, a print + server; and an application server. While all three were BDCs, typically only the print server would + service network logon requests after the first 10 users had started to use the network. This was + a reflection of the service load placed on both the application server and the data server. + </para> + + <para> + As unsatisfactory as the answer might sound, it all depends on network and server load + characteristics. + </para> + + </answer> + </qandaentry> + + <qandaentry> + <question> + + <para> + <indexterm><primary>NIS server</primary></indexterm><indexterm><primary>LDAP</primary></indexterm> + I've heard that you can store NIS accounts in LDAP. Is LDAP not just a smarter way to + run an NIS server? + </para> + + </question> + <answer> + + <para> + The correct answer to both questions is yes. But do understand that an LDAP server has + a configurable schema that can store far more information for many more purposes than + just NIS. + </para> + + </answer> + </qandaentry> + + <qandaentry> + <question> + + <para> + Can I use NIS in place of LDAP? + </para> + + </question> + <answer> + + <para> + <indexterm><primary>NIS</primary></indexterm> + <indexterm><primary>NIS schema</primary></indexterm> + No. The NIS database does not have provision to store Microsoft encrypted passwords and does not deal + with the types of data necessary for interoperability with Microsoft Windows networking. The use + of LDAP with Samba requires the use of a number of schemas, one of which is the NIS schema, but also + a Samba-specific schema extension. + </para> + +</answer> + </qandaentry> + + </qandaset> +</sect1> + +</chapter> + |