diff options
| -rw-r--r-- | docs/Samba3-HOWTO/TOSHARG-NetworkBrowsing.xml | 14 | ||||
| -rw-r--r-- | docs/Samba3-HOWTO/TOSHARG-Securing.xml | 263 | ||||
| -rw-r--r-- | docs/Samba3-HOWTO/TOSHARG-locking.xml | 89 |
3 files changed, 220 insertions, 146 deletions
diff --git a/docs/Samba3-HOWTO/TOSHARG-NetworkBrowsing.xml b/docs/Samba3-HOWTO/TOSHARG-NetworkBrowsing.xml index c5a5d7633a..379cc449e7 100644 --- a/docs/Samba3-HOWTO/TOSHARG-NetworkBrowsing.xml +++ b/docs/Samba3-HOWTO/TOSHARG-NetworkBrowsing.xml @@ -1641,6 +1641,20 @@ Some people find browsing fails because they do not have the global IPC$ connection that lists the shares is done as guest and so you must have a valid guest account. </para> +<note><para> +<indexterm><primary>IPC$</primary></indexterm> +<indexterm><primary>Windows Explorer</primary></indexterm> +<indexterm><primary>browse resources</primary></indexterm> +<indexterm><primary>Network Neighborhood</primary></indexterm> +<indexterm><primary>My Network Places</primary></indexterm> +The <literal>IPC$</literal> share is used by all SMB/CIFS clients to obtain the list of resources +that is available on the server. This is the source of the list of shares and printers when browsing +an SMB/CIFS server (also Windows machines) using the Windows Explorer to browse resources through +the Windows Network Neighborhood (also called My Network Places) through to a Windows server. At +this point the client has opened a connection to the <literal>\\server\IPC4</literal> resource. +Clicking on a share will then open up a connection to the <literal>\\server\share</literal>. +</para></note> + <para> <indexterm><primary>guest account</primary></indexterm> <indexterm><primary>anonymous access</primary></indexterm> diff --git a/docs/Samba3-HOWTO/TOSHARG-Securing.xml b/docs/Samba3-HOWTO/TOSHARG-Securing.xml index a35c48e807..00ac4591fc 100644 --- a/docs/Samba3-HOWTO/TOSHARG-Securing.xml +++ b/docs/Samba3-HOWTO/TOSHARG-Securing.xml @@ -12,10 +12,23 @@ <sect1> <title>Introduction</title> + <para> -This note was attached to the Samba 2.2.8 release notes because it contains an -important security fix. The information contained here applies to Samba -installations in general. +<indexterm><primary>security</primary></indexterm> +<indexterm><primary>direct internet access</primary></indexterm> +<indexterm><primary>firewall</primary></indexterm> +<indexterm><primary>private network</primary></indexterm> +<indexterm><primary>barriers</primary></indexterm> +<indexterm><primary>deterents</primary></indexterm> +<indexterm><primary>secured networks</primary></indexterm> +The information contained in this chapter applies in general to all Samba installations. Security us +everyone's concern in the information technology world. A surprising number of Samba servers are being +installed on machines that have direct internet access, thus security is made more critical than had the +server been located behind a firewall and on a private network. Paranoia regarding server security is causing +some network administrators to insist on the installation of robust firewalls even on server that are located +inside secured networks. This chapter provides brief information to assist the administrator who understands +how to create the needed barriers and deterents against <quote>the enemy</quote>, no matter where [s]he may +come from. </para> <blockquote> @@ -38,6 +51,10 @@ of knowledge with which we may unlock the secrets of the masters. <title>Features and Benefits</title> <para> +<indexterm><primary>moderately secure</primary></indexterm> +<indexterm><primary>perimeter firewall</primary></indexterm> +<indexterm><primary>host security</primary></indexterm> +<indexterm><primary>Samba security</primary></indexterm> There are three levels at which security principles must be observed in order to render a site at least moderately secure. They are the perimeter firewall, the configuration of the host server that is running Samba, and Samba itself. @@ -49,16 +66,21 @@ the latest protocols to permit more secure MS Windows file and print operations. </para> <para> -Samba may be secured from connections that originate from outside the local network. This may be -done using <emphasis>host-based protection</emphasis>, using Samba's implementation of a technology -known as <quote>tcpwrappers,</quote> or it may be done be using <emphasis>interface-based exclusion</emphasis> -so &smbd; will bind only to specifically permitted interfaces. It is also -possible to set specific share or resource-based exclusions, for example, on the <smbconfsection name="[IPC$]"/> -autoshare. The <smbconfsection name="[IPC$]"/> share is used for browsing purposes as well as to establish -TCP/IP connections. +<indexterm><primary>host-based protection</primary></indexterm> +<indexterm><primary>interface-based exclusion</primary></indexterm> +<indexterm><primary>resource-based exclusion</primary></indexterm> +Samba can be secured from connections that originate from outside the local network. This can be done using +<emphasis>host-based protection</emphasis>, using Samba's implementation of a technology known as +<quote>tcpwrappers,</quote> or it may be done be using <emphasis>interface-based exclusion</emphasis> so +&smbd; will bind only to specifically permitted interfaces. It is also possible to set specific share or +resource-based exclusions, for example, on the <smbconfsection name="[IPC$]"/> autoshare. The <smbconfsection +name="[IPC$]"/> share is used for browsing purposes as well as to establish TCP/IP connections. </para> <para> +<indexterm><primary>Access Control Entries</primary><see>ACE</see></indexterm> +<indexterm><primary>ACL</primary></indexterm> +<indexterm>controls<primary></primary></indexterm> Another method by which Samba may be secured is by setting Access Control Entries (ACEs) in an Access Control List (ACL) on the shares themselves. This is discussed in <link linkend="AccessControls">File, Directory, and Share Access Controls</link>. @@ -81,6 +103,9 @@ before someone will find yet another vulnerability. <title>Using Host-Based Protection</title> <para> +<indexterm><primary>outside threat</primary></indexterm> +<indexterm><primary>insecure</primary></indexterm> +<indexterm><primary>Internet</primary></indexterm> In many installations of Samba, the greatest threat comes from outside your immediate network. By default, Samba accepts connections from any host, which means that if you run an insecure version of Samba on @@ -89,21 +114,25 @@ before someone will find yet another vulnerability. </para> <para> +<indexterm><primary>allow access</primary></indexterm> +<indexterm><primary>range of hosts</primary></indexterm> One of the simplest fixes in this case is to use the <smbconfoption name="hosts allow"/> and <smbconfoption name="hosts deny"/> options in the Samba &smb.conf; configuration file to allow access to your server only from a specific range of hosts. An example might be: + <smbconfblock> + <smbconfoption name="hosts allow">127.0.0.1 192.168.2.0/24 192.168.3.0/24</smbconfoption> + <smbconfoption name="hosts deny">0.0.0.0/0</smbconfoption> + </smbconfblock> </para> - <para><smbconfblock> -<smbconfoption name="hosts allow">127.0.0.1 192.168.2.0/24 192.168.3.0/24</smbconfoption> -<smbconfoption name="hosts deny">0.0.0.0/0</smbconfoption> - </smbconfblock></para> - <para> +<indexterm><primary>localhost</primary></indexterm> +<indexterm><primary>private networks</primary></indexterm> +<indexterm><primary>called name</primary></indexterm> The above will allow SMB connections only from <constant>localhost</constant> (your own computer) and from the two private networks 192.168.2 and 192.168.3. All other connections will be refused as soon as the client sends its first packet. The refusal - will be marked as <errorname>not listening on called name</errorname> error. + will be marked as <literal>not listening on called name</literal> error. </para> </sect2> @@ -114,13 +143,13 @@ before someone will find yet another vulnerability. <para> If you want to restrict access to your server to valid users only, then the following method may be of use. In the &smb.conf; <smbconfsection name="[global]"/> section put: + <smbconfblock> + <smbconfoption name="valid users">@smbusers, jacko</smbconfoption> + </smbconfblock> </para> - <para><smbconfblock> -<smbconfoption name="valid users">@smbusers, jacko</smbconfoption> - </smbconfblock></para> - <para> +<indexterm><primary>smbusers</primary></indexterm> This restricts all server access either to the user <emphasis>jacko</emphasis> or to members of the system group <emphasis>smbusers</emphasis>. </para> @@ -132,6 +161,9 @@ before someone will find yet another vulnerability. <title>Using Interface Protection</title> <para> +<indexterm><primary>network interface</primary></indexterm> +<indexterm><primary>accept connections</primary></indexterm> +<indexterm><primary>Internet</primary></indexterm> By default, Samba accepts connections on any network interface that it finds on your system. That means if you have an ISDN line or a PPP connection to the Internet then Samba will accept connections on those @@ -140,27 +172,46 @@ before someone will find yet another vulnerability. <para> You can change this behavior using options like this: + <smbconfblock> + <smbconfoption name="interfaces">eth* lo</smbconfoption> + <smbconfoption name="bind interfaces only">yes</smbconfoption> + </smbconfblock> </para> - <para><smbconfblock> -<smbconfoption name="interfaces">eth* lo</smbconfoption> -<smbconfoption name="bind interfaces only">yes</smbconfoption> - </smbconfblock></para> + <para> +<indexterm><primary>interfaces</primary></indexterm> +<indexterm><primary>loopback interface</primary></indexterm> +<indexterm><primary>Ethernet adapters</primary></indexterm> +<indexterm><primary>listen for connections</primary></indexterm> + This tells Samba to listen for connections only on interfaces with a name starting with + <constant>eth</constant> such as <constant>eth0 or eth1</constant>, plus on the loopback interface called + <constant>lo</constant>. The name you will need to use depends on what OS you are using. In the above, I used + the common name for Ethernet adapters on Linux. + </para> <para> - This tells Samba to only listen for connections on interfaces with a - name starting with <constant>eth</constant> such as <constant>eth0 or eth1</constant>, plus on the loopback - interface called <constant>lo</constant>. The name you will need to use depends on what - OS you are using. In the above, I used the common name for Ethernet - adapters on Linux. +<indexterm><primary>PPP</primary></indexterm> +<indexterm><primary>SMB</primary></indexterm> +<indexterm><primary>cracker</primary></indexterm> +<indexterm><primary>confirm address</primary></indexterm> + If you use the above and someone tries to make an SMB connection to your host over a PPP interface called + <constant>ppp0,</constant> then [s]he will get a TCP connection refused reply. In that case, no Samba code + is run at all, because the operating system has been told not to pass connections from that interface to any + Samba process. However, the refusal helps a would-be cracker by confirming that the IP address provides + valid active services. </para> <para> - If you use the above and someone tries to make an SMB connection to - your host over a PPP interface called <constant>ppp0,</constant> then he or she will get a TCP - connection refused reply. In that case, no Samba code is run at all because - the operating system has been told not to pass connections from that - interface to any Samba process. +<indexterm><primary>ignore connection</primary></indexterm> +<indexterm><primary>refusing connection</primary></indexterm> +<indexterm><primary>exploitation</primary></indexterm> +<indexterm><primary>denial of service</primary></indexterm> +<indexterm><primary>firewall</primary></indexterm> + A better response would be to ignore the connection (from, e.g., ppp0) altogether. The + advantage of ignoring the connection attempt, as compared with refusing it, is that it foils those who + probe an interface with the sole intention of finding valid IP addresses for later use in exploitation + or denial of service attacks. This method of dealing with potential malicious activity demands the + use of appropriate firewall mechanisms. </para> </sect2> @@ -169,36 +220,45 @@ before someone will find yet another vulnerability. <title>Using a Firewall</title> <para> - Many people use a firewall to deny access to services they do not - want exposed outside their network. This can be a good idea, - although I recommend using it in conjunction with the above - methods so you are protected even if your firewall is not active - for some reason. +<indexterm><primary>deny access</primary></indexterm> +<indexterm><primary>exposed</primary></indexterm> +<indexterm><primary>firewall active</primary></indexterm> + Many people use a firewall to deny access to services they do not want exposed outside their network. This can + be a good idea, although I recommend using it in conjunction with the above methods so you are protected even + if your firewall is not active for some reason. </para> <para> - If you are setting up a firewall, you need to know what TCP and - UDP ports to allow and block. Samba uses the following: + If you are setting up a firewall, you need to know what TCP and UDP ports to allow and block. Samba uses + the following: +<indexterm><primary>Port 135/TCP</primary></indexterm> +<indexterm><primary>Port 137/UDP</primary></indexterm> +<indexterm><primary>Port 138/UDP</primary></indexterm> +<indexterm><primary>Port 139/TCP</primary></indexterm> +<indexterm><primary>Port 445/TCP</primary></indexterm> </para> <simplelist> - <member>UDP/137 - used by nmbd</member> - <member>UDP/138 - used by nmbd</member> - <member>TCP/139 - used by smbd</member> - <member>TCP/445 - used by smbd</member> + <member>Port 135/TCP - used by smbd</member> + <member>Port 137/UDP - used by nmbd</member> + <member>Port 138/UDP - used by nmbd</member> + <member>Port 139/TCP - used by smbd</member> + <member>Port 445/TCP - used by smbd</member> </simplelist> <para> - The last one is important because many older firewall setups may not be - aware of it, given that this port was only added to the protocol in - recent years. +<indexterm><primary>firewall setups</primary></indexterm> + The last one is important because many older firewall setups may not be aware of it, given that this port + was only added to the protocol in recent years. </para> <para> - When configuring a firewall, the high order ports (1024-65535) are often - used for outgoing connections and therefore should be permitted through the - firewall. It is prudent to block incoming packets on the high order ports - except for established connections. +<indexterm><primary>configuring a firewall</primary></indexterm> +<indexterm><primary>high order ports</primary></indexterm> +<indexterm><primary>block incoming packets</primary></indexterm> + When configuring a firewall, the high order ports (1024-65535) are often used for outgoing connections and + therefore should be permitted through the firewall. It is prudent to block incoming packets on the high order + ports except for established connections. </para> </sect2> @@ -207,37 +267,41 @@ before someone will find yet another vulnerability. <title>Using IPC$ Share-Based Denials </title> <para> - If the above methods are not suitable, then you could also place a - more specific deny on the IPC$ share that is used in the recently - discovered security hole. This allows you to offer access to other - shares while denying access to IPC$ from potentially untrustworthy - hosts. +<indexterm><primary>IPC$</primary></indexterm> +<indexterm><primary>deny</primary></indexterm> +<indexterm><primary>security hole</primary></indexterm> + If the above methods are not suitable, then you could also place a more specific deny on the IPC$ share that + is used in the recently discovered security hole. This allows you to offer access to other shares while + denying access to IPC$ from potentially untrustworthy hosts. </para> <para> To do this you could use: + <smbconfblock> + <smbconfsection name="[IPC$]"/> + <smbconfoption name="hosts allow">192.168.115.0/24 127.0.0.1</smbconfoption> + <smbconfoption name="hosts deny">0.0.0.0/0</smbconfoption> + </smbconfblock> </para> - <para><smbconfblock> -<smbconfsection name="[IPC$]"/> -<smbconfoption name="hosts allow">192.168.115.0/24 127.0.0.1</smbconfoption> -<smbconfoption name="hosts deny">0.0.0.0/0</smbconfoption> - </smbconfblock></para> - <para> - This instructs Samba that IPC$ connections are not allowed from - anywhere except the two listed network addresses (localhost and the 192.168.115 - subnet). Connections to other shares are still allowed. Because the - IPC$ share is the only share that is always accessible anonymously, - this provides some level of protection against attackers who do not - know a valid username/password for your host. +<indexterm><primary>IPC$</primary></indexterm> +<indexterm><primary>protection against attackers</primary></indexterm> +<indexterm><primary>valid username/password</primary></indexterm> + This instructs Samba that IPC$ connections are not allowed from anywhere except the two listed network + addresses (localhost and the 192.168.115 subnet). Connections to other shares are still allowed. Because the + IPC$ share is the only share that is always accessible anonymously, this provides some level of protection + against attackers who do not know a valid username/password for your host. </para> <para> - If you use this method, then clients will be given an <errorname>`access denied'</errorname> - reply when they try to access the IPC$ share. Those clients will not be able to - browse shares and may also be unable to access some other resources. This is not - recommended unless for some reason you cannot use one of the other methods just discussed. +<indexterm><primary>access denied</primary></indexterm> +<indexterm><primary>IPC$</primary></indexterm> +<indexterm><primary>browse shares</primary></indexterm> + If you use this method, then clients will be given an <literal>`access denied'</literal> reply when they try + to access the IPC$ share. Those clients will not be able to browse shares and may also be unable to access + some other resources. This is not recommended unless for some reason you cannot use one of the other methods + just discussed. </para> </sect2> @@ -246,6 +310,7 @@ before someone will find yet another vulnerability. <title>NTLMv2 Security</title> <para> +<indexterm><primary>NTLMv2</primary></indexterm> To configure NTLMv2 authentication, the following registry keys are worth knowing about: </para> @@ -281,10 +346,13 @@ before someone will find yet another vulnerability. <title>Upgrading Samba</title> <para> -Please check regularly on <ulink noescape="1" url="http://www.samba.org/">http://www.samba.org/</ulink> for updates and -important announcements. Occasionally security releases are made, and -it is highly recommended to upgrade Samba when a security vulnerability -is discovered. Check with your OS vendor for OS-specific upgrades. +<indexterm><primary>updates</primary></indexterm> +<indexterm><primary>important announcements</primary></indexterm> +<indexterm><primary>security vulnerability</primary></indexterm> +Please check regularly on <ulink noescape="1" url="http://www.samba.org/">http://www.samba.org/</ulink> for +updates and important announcements. Occasionally security releases are made, and it is highly recommended to +upgrade Samba promptly when a security vulnerability is discovered. Check with your OS vendor for OS-specific +upgrades. </para> </sect1> @@ -293,17 +361,17 @@ is discovered. Check with your OS vendor for OS-specific upgrades. <title>Common Errors</title> <para> -If all of Samba and host platform configurations were really as intuitive as one might like them to be, this -section would not be necessary. Security issues are often vexing for a support person to resolve, not -because of the complexity of the problem, but because most administrators who post what turns -out to be a security problem request are totally convinced that the problem is with Samba. +If all Samba and host platform configurations were really as intuitive as one might like them to be, this +chapter would not be necessary. Security issues are often vexing for a support person to resolve, not because +of the complexity of the problem, but because most administrators who post what turns out to be a security +problem request are totally convinced that the problem is with Samba. </para> <sect2> <title>Smbclient Works on Localhost, but the Network Is Dead</title> <para> - This is a common problem. Red Hat Linux (and others) installs a default firewall. + This is a common problem. Linux vendors tend to install a default firewall. With the default firewall in place, only traffic on the loopback adapter (IP address 127.0.0.1) is allowed through the firewall. </para> @@ -317,36 +385,41 @@ out to be a security problem request are totally convinced that the problem is w </sect2> <sect2> - <title>Why Can Users Access Home Directories of Other Users?</title> + <title>Why Can Users Access Other Users Home Directories?</title> <para> <quote> - We are unable to keep individual users from mapping to any other user's - home directory once they have supplied a valid password! They only need - to enter their own password. I have not found any method to configure - Samba so that users may map only their own home directory. +<indexterm><primary>mapping home directory</primary></indexterm> +<indexterm><primary>own home directory</primary></indexterm> + We are unable to keep individual users from mapping to any other user's home directory once they have + supplied a valid password! They only need to enter their own password. I have not found any method to + configure Samba so that users may map only their own home directory. </quote> </para> <para><quote> - User xyzzy can map his home directory. Once mapped, user xyzzy can also map - anyone else's home directory. + User xyzzy can map his home directory. Once mapped, user xyzzy can also map anyone else's home directory. </quote></para> <para> - This is not a security flaw, it is by design. Samba allows users to have - exactly the same access to the UNIX file system as when they were logged - onto the UNIX box, except that it only allows such views onto the file +<indexterm><primary>security flaw</primary></indexterm> +<indexterm><primary>defined shares</primary></indexterm> + This is not a security flaw, it is by design. Samba allows users to have exactly the same access to the UNIX + file system as when they were logged onto the UNIX box, except that it only allows such views onto the file system as are allowed by the defined shares. </para> <para> +<indexterm><primary>UNIX home directories</primary></indexterm> +<indexterm><primary>permissions</primary></indexterm> If your UNIX home directories are set up so that one user can happily <command>cd</command> into another user's directory and execute <command>ls</command>, the UNIX security solution is to change file permissions on the user's home directories so that the <command>cd</command> and <command>ls</command> are denied. </para> <para> +<indexterm><primary>security policies</primary></indexterm> +<indexterm><primary>permissions</primary></indexterm> Samba tries very hard not to second guess the UNIX administrator's security policies and trusts the UNIX admin to set the policies and permissions he or she desires. </para> @@ -360,11 +433,11 @@ out to be a security problem request are totally convinced that the problem is w The <smbconfoption name="only user"></smbconfoption> works in conjunction with the <smbconfoption name="users">list</smbconfoption>, so to get the behavior you require, add the line: <smbconfblock> -<smbconfoption name="users">%S</smbconfoption> -</smbconfblock> + <smbconfoption name="users">%S</smbconfoption> + </smbconfblock> This is equivalent to adding <smbconfblock> -<smbconfoption name="valid users">%S</smbconfoption> + <smbconfoption name="valid users">%S</smbconfoption> </smbconfblock> to the definition of the <smbconfsection name="[homes]"/> share, as recommended in the &smb.conf; man page. diff --git a/docs/Samba3-HOWTO/TOSHARG-locking.xml b/docs/Samba3-HOWTO/TOSHARG-locking.xml index e76f456ffa..4a433fb6c3 100644 --- a/docs/Samba3-HOWTO/TOSHARG-locking.xml +++ b/docs/Samba3-HOWTO/TOSHARG-locking.xml @@ -69,7 +69,7 @@ server as well as on each MS Windows client! <indexterm><primary>deny modes</primary></indexterm> There are two types of locking that need to be performed by an SMB server. The first is <emphasis>record locking</emphasis> that allows a client to lock -a range of bytes in a open file. The second is the <emphasis>deny modes</emphasis> +a range of bytes in an open file. The second is the <emphasis>deny modes</emphasis> that are specified when a file is open. </para> @@ -92,7 +92,7 @@ many more differences, too many to be listed here. <para> <indexterm><primary>record locking</primary></indexterm> <indexterm><primary>byte-range lock</primary></indexterm> -Samba 2.2 and above implement record locking completely independent of the +Samba 2.2 and above implement record locking completely independently of the underlying UNIX system. If a byte-range lock that the client requests happens to fall into the range of 0 to 2^31, Samba hands this request down to the UNIX system. No other locks can be seen by UNIX, anyway. @@ -103,8 +103,8 @@ No other locks can be seen by UNIX, anyway. <indexterm><primary>rpc.lockd</primary></indexterm> Strictly speaking, an SMB server should check for locks before every read and write call on a file. Unfortunately, with the way fcntl() works, this can be slow and may overstress -the <command>rpc.lockd</command>. This is almost always unnecessary because clients are supposed to -independently make locking calls before reads and writes if locking is +the <command>rpc.lockd</command>. This is almost always unnecessary because clients are +independently supposed to make locking calls before reads and writes if locking is important to them. By default, Samba only makes locking calls when explicitly asked to by a client, but if you set <smbconfoption name="strict locking">yes</smbconfoption>, it will make lock checking calls on <emphasis>every</emphasis> read and write call. @@ -450,13 +450,10 @@ regularly opening the same file. <indexterm><primary>Multiuser databases</primary></indexterm> <indexterm><primary>management bottleneck</primary></indexterm> <indexterm><primary>oplocks disabled</primary></indexterm> -Multiuser databases clearly pose a risk due to their very nature &smbmdash; -they are typically heavily accessed by numerous users at random -intervals. Placing a multiuser database on a share with oplocks -enabled will likely result in a locking management bottleneck -on the Samba server. Whether the database application is developed -in-house or a commercially available product, ensure that the share -has oplocks disabled. +Multiuser databases clearly pose a risk due to their very nature &smbmdash; they are typically heavily +accessed by numerous users at random intervals. Placing a multiuser database on a share with oplocks enabled +will likely result in a locking management bottleneck on the Samba server. Whether the database application is +developed in-house or a commercially available product, ensure that the share has oplocks disabled. </para> </sect3> @@ -470,18 +467,13 @@ has oplocks disabled. <indexterm><primary>client-side data caching</primary></indexterm> <indexterm><primary>oplocks management</primary></indexterm> <indexterm><primary>disabling oplocks</primary></indexterm> -Process data management (PDM) applications such as IMAN, Enovia, and -Clearcase are increasing in usage with Windows client platforms and -therefore with SMB datastores. PDM applications manage multiuser -environments for critical data security and access. The typical PDM -environment is usually associated with sophisticated client design -applications that will load data locally as demanded. In addition, the -PDM application will usually monitor the data state of each client. -In this case, client-side data caching is best left to the local -application and PDM server to negotiate and maintain. It is -appropriate to eliminate the client OS from any caching tasks, and the -server from any oplocks management, by disabling oplocks on -the share. +Process data management (PDM) applications such as IMAN, Enovia, and Clearcase are increasing in usage with +Windows client platforms and therefore with SMB datastores. PDM applications manage multiuser environments for +critical data security and access. The typical PDM environment is usually associated with sophisticated client +design applications that will load data locally as demanded. In addition, the PDM application will usually +monitor the data state of each client. In this case, client-side data caching is best left to the local +application and PDM server to negotiate and maintain. It is appropriate to eliminate the client OS from any +caching tasks, and the server from any oplocks management, by disabling oplocks on the share. </para> </sect3> @@ -491,16 +483,12 @@ the share. <para> <indexterm><primary>oplock break</primary></indexterm> -Samba includes an &smb.conf; parameter called -<smbconfoption name="force user"/> that changes -the user accessing a share from the incoming user to whatever user is -defined by the smb.conf variable. If oplocks is enabled -on a share, the change in user access causes an oplock break to be sent -to the client, even if the user has not explicitly loaded a file. In -cases where the network is slow or unreliable, an oplock break can -become lost without the user even accessing a file. This can cause -apparent performance degradation as the client continually reconnects -to overcome the lost oplock break. +Samba includes an &smb.conf; parameter called <smbconfoption name="force user"/> that changes the user +accessing a share from the incoming user to whatever user is defined by the &smb.conf; variable. If oplocks is +enabled on a share, the change in user access causes an oplock break to be sent to the client, even if the +user has not explicitly loaded a file. In cases where the network is slow or unreliable, an oplock break can +become lost without the user even accessing a file. This can cause apparent performance degradation as the +client continually reconnects to overcome the lost oplock break. </para> <para> @@ -542,7 +530,7 @@ likely cause problems. The parameters are <para> <indexterm><primary>turn oplocks off</primary></indexterm> For most users, administrators, and environments, if these parameters -are required, then the better option is to simply turn oplocks off. +are required, then the better option is simply to turn oplocks off. The Samba SWAT help text for both parameters reads: <quote>Do not change this parameter unless you have read and understood the Samba oplock code.</quote> This is good advice. @@ -1096,6 +1084,7 @@ tdb(/usr/local/samba_2.2.7/var/locks/locking.tdb): rec_read bad magic <sect2> <title>Problems Saving Files in MS Office on Windows XP</title> +<indexterm><primary>KB 812937</primary></indexterm> <para>This is a bug in Windows XP. More information can be found in <ulink url="http://support.microsoft.com/?id=812937">Microsoft Knowledge Base article 812937</ulink></para>. @@ -1107,6 +1096,7 @@ tdb(/usr/local/samba_2.2.7/var/locks/locking.tdb): rec_read bad magic <para><quote>It sometimes takes approximately 35 seconds to delete files over the network after XP SP1 has been applied.</quote></para> +<indexterm><primary>KB 811492</primary></indexterm> <para>This is a bug in Windows XP. More information can be found in <ulink url="http://support.microsoft.com/?id=811492"> Microsoft Knowledge Base article 811492</ulink></para>. </sect2> @@ -1117,9 +1107,9 @@ tdb(/usr/local/samba_2.2.7/var/locks/locking.tdb): rec_read bad magic <title>Additional Reading</title> <para> -You may want to check for an updated version of this white paper on our Web site from -time to time. Many of our white papers are updated as information changes. For those papers, -the last edited date is always at the top of the paper. +You may want to check for an updated documentation regarding file and record locking issues on the Microsoft +<ulink url="http://support.microsoft.com/">Support</ulink> web site. Additionally, a search for the work +<literal>locking</literal> on the Samba <ulink url="http://www.samba.org/">web</ulink> site. </para> <para> @@ -1127,26 +1117,23 @@ Section of the Microsoft MSDN Library on opportunistic locking: </para> <para> -Opportunistic Locks, Microsoft Developer Network (MSDN), Windows Development > -Windows Base Services > Files and I/O > SDK Documentation > File Storage > File Systems -> About File Systems > Opportunistic Locks, Microsoft Corporation -<ulink noescape="1" url="http://msdn.microsoft.com/library/en-us/fileio/storage_5yk3.asp">http://msdn.microsoft.com/library/en-us/fileio/storage_5yk3.asp</ulink>. +<indexterm><primary>KB 224992</primary></indexterm> +Microsoft Knowledge Base, <quote>Maintaining Transactional Integrity with OPLOCKS</quote>, +Microsoft Corporation, April 1999, <ulink noescape="1" url="http://support.microsoft.com/?id=224992">Microsoft +KB Article 224992</ulink>. </para> <para> - Microsoft Knowledge Base Article Q224992, <?latex \linebreak ?><quote>Maintaining Transactional Integrity -with OPLOCKS</quote>, -Microsoft Corporation, April 1999, <ulink noescape="1" url="http://support.microsoft.com/default.aspx?scid=kb;en-us;Q224992">http://support.microsoft.com/default.aspx?scid=kb;en-us;Q224992</ulink>. +<indexterm><primary>KB 296264</primary></indexterm> +Microsoft Knowledge Base, <quote>Configuring Opportunistic Locking in Windows 2000</quote>, +Microsoft Corporation, April 2001 <ulink noescape="1" url="http://support.microsoft.com/?id=296264">Microsoft KB Article 296264</ulink>. </para> <para> -Microsoft Knowledge Base Article Q296264, <quote>Configuring Opportunistic Locking in Windows 2000</quote>, -Microsoft Corporation, April 2001 <ulink noescape="1" url="http://support.microsoft.com/default.aspx?scid=kb;en-us;Q296264">http://support.microsoft.com/default.aspx?scid=kb;en-us;Q296264</ulink>. -</para> - -<para> -Microsoft Knowledge Base Article Q129202, <quote>PC Ext: Explanation of Opportunistic Locking on Windows NT</quote>, -Microsoft Corporation, April 1995 <ulink noescape="1" url="http://support.microsoft.com/default.aspx?scid=kb;en-us;Q129202">http://support.microsoft.com/default.aspx?scid=kb;en-us;Q129202</ulink>. +<indexterm><primary>KB 129202</primary></indexterm> +Microsoft Knowledge Base, <quote>PC Ext: Explanation of Opportunistic Locking on Windows NT</quote>, +Microsoft Corporation, April 1995 <ulink noescape="1" url="http://support.microsoft.com/?id=129202">Microsoft +KB Article 129202</ulink>. </para> </sect1> |