From 83a17815a7689f1f6f7ca57161a0e804277c75f9 Mon Sep 17 00:00:00 2001 From: Jelmer Vernooij Date: Sun, 20 Jun 2004 12:43:16 +0000 Subject: New structure for the docs: - Same name for a doc everywhere (howto -> Samba-HOWTO-Collection, etc) - Shorter and more clearly structured Makefile - Make it possible to change the paths for the images (This used to be commit 96f6c05f25acc8a9bb1977b8bd5cc97ce511b6b1) --- docs/Samba-HOWTO-Collection/InterdomainTrusts.xml | 478 ++++++++++++++++++++++ 1 file changed, 478 insertions(+) create mode 100644 docs/Samba-HOWTO-Collection/InterdomainTrusts.xml (limited to 'docs/Samba-HOWTO-Collection/InterdomainTrusts.xml') diff --git a/docs/Samba-HOWTO-Collection/InterdomainTrusts.xml b/docs/Samba-HOWTO-Collection/InterdomainTrusts.xml new file mode 100644 index 0000000000..78e92db5a8 --- /dev/null +++ b/docs/Samba-HOWTO-Collection/InterdomainTrusts.xml @@ -0,0 +1,478 @@ + + + %global_entities; +]> + + + + &author.jht; + &author.mimir; + &person.jelmer;drawing + + StephenLangasek + +
vorlon@netexpress.net
+ + + April 3, 2003 + + +Interdomain Trust Relationships + + + +Interdomain Trusts +Samba-3 supports NT4-style domain trust relationships. This is a feature that many sites +will want to use if they migrate to Samba-3 from an NT4-style domain and do not want to +adopt Active Directory or an LDAP-based authentication backend. This section explains +some background information regarding trust relationships and how to create them. It is now +possible for Samba-3 to trust NT4 (and vice versa), as well as to create Samba-to-Samba +trusts. + + + +Features and Benefits + + +Samba-3 can participate in Samba-to-Samba as well as in Samba-to-MS Windows NT4-style +trust relationships. This imparts to Samba similar scalability as with MS Windows NT4. + + + +Given that Samba-3 has the capability to function with a scalable backend authentication +database such as LDAP, and given its ability to run in Primary as well as Backup Domain Control +modes, the administrator would be well advised to consider alternatives to the use of +Interdomain trusts simply because by the very nature of how this works it is fragile. +That was, after all, a key reason for the development and adoption of Microsoft Active Directory. + + + + + +Trust Relationship Background + + +MS Windows NT3/4 type security domains employ a non-hierarchical security structure. +The limitations of this architecture as it effects the scalability of MS Windows networking +in large organizations is well known. Additionally, the flat namespace that results from +this design significantly impacts the delegation of administrative responsibilities in +large and diverse organizations. + + + +Microsoft developed Active Directory Service (ADS), based on Kerberos and LDAP, as a means +of circumventing the limitations of the older technologies. Not every organization is ready +or willing to embrace ADS. For small companies the older NT4-style domain security paradigm +is quite adequate, there remains an entrenched user base for whom there is no direct +desire to go through a disruptive change to adopt ADS. + + + +With MS Windows NT, Microsoft introduced the ability to allow differing security domains +to effect a mechanism so users from one domain may be given access rights and privileges +in another domain. The language that describes this capability is couched in terms of +Trusts. Specifically, one domain will trust the users +from another domain. The domain from which users are available to another security domain is +said to be a trusted domain. The domain in which those users have assigned rights and privileges +is the trusting domain. With NT3.x/4.0 all trust relationships are always in one direction only, +thus if users in both domains are to have privileges and rights in each others' domain, then it is +necessary to establish two relationships, one in each direction. + + + +In an NT4-style MS security domain, all trusts are non-transitive. This means that if there +are three domains (let's call them RED, WHITE and BLUE) where RED and WHITE have a trust +relationship, and WHITE and BLUE have a trust relationship, then it holds that there is no +implied trust between the RED and BLUE domains. Relationships are explicit and not +transitive. + + + +New to MS Windows 2000 ADS security contexts is the fact that trust relationships are two-way +by default. Also, all inter-ADS domain trusts are transitive. In the case of the RED, WHITE and BLUE +domains above, with Windows 2000 and ADS the RED and BLUE domains can trust each other. This is +an inherent feature of ADS domains. Samba-3 implements MS Windows NT4-style Interdomain trusts +and interoperates with MS Windows 200x ADS security domains in similar manner to MS Windows NT4-style domains. + + + + + +Native MS Windows NT4 Trusts Configuration + + +There are two steps to creating an interdomain trust relationship. To effect a two-way trust +relationship, it is necessary for each domain administrator to create a trust account for the +other domain to use in verifying security credentials. +Interdomain Trustscreating + + + + +Creating an NT4 Domain Trust + + +For MS Windows NT4, all domain trust relationships are configured using the +Domain User Manager. This is done from the Domain User Manager Policies +entry on the menu bar. From the Policy menu, select +Trust Relationships. Next to the lower box labeled +Permitted to Trust this Domain are two buttons, Add +and Remove. The Add button will open a panel in which +to enter the name of the remote domain that will be able to assign access rights to users in +your domain. You will also need to enter a password for this trust relationship, which the +trusting domain will use when authenticating users from the trusted domain. +The password needs to be typed twice (for standard confirmation). + + + + + + +Completing an NT4 Domain Trust + + +Interdomain TrustsCompleting +A trust relationship will work only when the other (trusting) domain makes the appropriate connections +with the trusted domain. To consummate the trust relationship, the administrator will launch the +Domain User Manager from the menu select Policies, then select +Trust Relationships, click on the Add button +next to the box that is labeled Trusted Domains. A panel will open in which +must be entered the name of the remote domain as well as the password assigned to that trust. + + + + + +Inter-Domain Trust Facilities + + + +Interdomain TrustsFacilities +A two-way trust relationship is created when two one-way trusts are created, one in each direction. +Where a one-way trust has been established between two MS Windows NT4 domains (let's call them +DomA and DomB), the following facilities are created: + + +trusts1Trusts overview. + + + + DomA (completes the trust connection) Trusts DomB. + + + + DomA is the Trusting domain. + + + + DomB is the Trusted domain (originates the trust account). + + + + Users in DomB can access resources in DomA. + + + + Users in DomA cannot access resources in DomB. + + + + Global groups from DomB can be used in DomA. + + + + Global groups from DomA cannot be used in DomB. + + + + DomB does appear in the logon dialog box on client workstations in DomA. + + + + DomA does not appear in the logon dialog box on client workstations in DomB. + + + + + + Users/Groups in a trusting domain cannot be granted rights, permissions or access + to a trusted domain. + + + + The trusting domain can access and use accounts (Users/Global Groups) in the + trusted domain. + + + + Administrators of the trusted domain can be granted administrative rights in the + trusting domain. + + + + Users in a trusted domain can be given rights and privileges in the trusting + domain. + + + + Trusted domain Global Groups can be given rights and permissions in the trusting + domain. + + + + Global Groups from the trusted domain can be made members in Local Groups on + MS Windows Domain Member machines. + + + + + + + + +Configuring Samba NT-Style Domain Trusts + + +This description is meant to be a fairly short introduction about how to set up a Samba server so +that it can participate in interdomain trust relationships. Trust relationship support in Samba +is at an early stage, so do not be surprised if something does not function as it should. + + + +Each of the procedures described below assumes the peer domain in the trust relationship is +controlled by a Windows NT4 server. However, the remote end could just as well be another +Samba-3 domain. It can be clearly seen, after reading this document, that combining +Samba-specific parts of what's written below leads to trust between domains in a purely Samba +environment. + + + +Samba as the Trusted Domain + + +In order to set the Samba PDC to be the trusted party of the relationship, you first need +to create a special account for the domain that will be the trusting party. To do that, +you can use the smbpasswd utility. Creating the trusted domain account is +similar to creating a trusted machine account. Suppose, your domain is +called SAMBA, and the remote domain is called RUMBA. The first step +will be to issue this command from your favorite shell: + + + + +&rootprompt; smbpasswd -a -i rumba +New SMB password: XXXXXXXX +Retype SMB password: XXXXXXXX +Added user rumba$ + + +where means to add a new account into the +passdb database and means: create this +account with the Inter-Domain trust flag. + + + +The account name will be rumba$ (the name of the remote domain). +If this fails, you should check that the trust account has been added to the system +password database (/etc/passwd). If it has not been added, you +can add it manually and then repeat the step above. + + + +After issuing this command, you will be asked to enter the password for +the account. You can use any password you want, but be aware that Windows NT will +not change this password until seven days following account creation. +After the command returns successfully, you can look at the entry for the new account +(in the standard way as appropriate for your configuration) and see that accounts name is +really RUMBA$ and it has the I flag set in the flags field. Now you are ready to confirm +the trust by establishing it from Windows NT Server. + + + + +User Manager +Open User Manager for Domains and from the +Policies menu, select Trust Relationships.... +Beside the Trusted domains list box click the +Add... button. You will be prompted for +the trusted domain name and the relationship password. Type in SAMBA, as this is +the name of the remote domain and the password used at the time of account creation. +Click on OK and, if everything went without incident, you will see +the Trusted domain relationship successfully +established message. + + + + +Samba as the Trusting Domain + + +This time activities are somewhat reversed. Again, we'll assume that your domain +controlled by the Samba PDC is called SAMBA and the NT-controlled domain is called RUMBA. + + + +The very first step is to add an account for the SAMBA domain on RUMBA's PDC. + + + + +User Manager +Launch the Domain User Manager, then from the menu select +Policies, Trust Relationships. +Now, next to the Trusted Domains box press the Add +button and type in the name of the trusted domain (SAMBA) and the password to use in securing +the relationship. + + + +The password can be arbitrarily chosen. It is easy to change the password +from the Samba server whenever you want. After confirming the password your account is +ready for use. Now its Samba's turn. + + + +Using your favorite shell while being logged in as root, issue this command: + + + +&rootprompt;net rpc trustdom establish rumba + + + +You will be prompted for the password you just typed on your Windows NT4 Server box. +An error message `NT_STATUS_NOLOGON_INTERDOMAIN_TRUST_ACCOUNT' +that may be reported periodically is of no concern and may safely be ignored. +It means the password you gave is correct and the NT4 Server says the account is ready for +interdomain connection and not for ordinary connection. After that, be patient; +it can take a while (especially in large networks), but eventually you should see +the Success message. Congratulations! Your trust +relationship has just been established. + + + +You have to run this command as root because you must have write access to +the secrets.tdb file. + + + + + + +NT4-Style Domain Trusts with Windows 2000 + +Although Domain User Manager is not present in Windows 2000, it is +also possible to establish an NT4-style trust relationship with a Windows 2000 domain +controller running in mixed mode as the trusting server. It should also be possible for +Samba to trust a Windows 2000 server, however, more testing is still needed in this area. + + + +After creating the interdomain trust account on the +Samba server as described above, open Active Directory Domains and +Trusts on the AD controller of the domain whose resources you wish Samba users +to have access to. Remember that since NT4-style trusts are not transitive, if you want +your users to have access to multiple mixed-mode domains in your AD forest, you will need to +repeat this process for each of those domains. With Active Directory Domains +and Trusts open, right-click on the name of the Active Directory domain that +will trust our Samba domain and choose Properties, then click on +the Trusts tab. In the upper part of the panel, you will see a list box +labeled Domains trusted by this domain:, and an +Add... button next to it. Press this button and just as with NT4, you +will be prompted for the trusted domain name and the relationship password. Press OK and +after a moment, Active Directory will respond with The trusted domain has +been added and the trust has been verified. Your Samba users can now be +granted access to resources in the AD domain. + + + + +Common Errors + + +Interdomain trust relationships should not be attempted on networks that are unstable +or that suffer regular outages. Network stability and integrity are key concerns with +distributed trusted domains. + + + +Browsing of Trusted Domain Fails + + +Browsing from a machine in a trusted Windows 200x Domain to a Windows 200x member of +a trusting samba domain, I get the following error: + + + +The system detected a possible attempt to compromise security. Please ensure that +you can contact the server that authenticated you. + + + +The event logs on the box I'm trying to connect to have entries regarding group +policy not being applied because it is a member of a down-level domain. + + +Answer: If there is a computer account in the Windows +200x Domain for the machine in question, and it is disabled, this problem can +occur. If there is no computer account (removed or never existed), or if that +account is still intact (i.e.: you just joined it to another domain) everything +seems to be fine. By default, when you un-join a domain (the Windows 200x +Domain), the computer tries to automatically disable the computer account in +the domain. If you are running as an account which has privileges to do this +when you un-join the machine, it is done, otherwise it is not done. + + + + + +Problems With LDAP ldapsam And The smbldap-tools + + +If you use the smbldap-useradd.pl script to create a trust +account to set up Interdomain trusts the process of setting up the trust will +fail. The account that was created in the LDAP database will have an account +flags field that has [W ], when it must have +[I ] for Interdomain trusts to work. + + +Answer: Here is a simple solution. +Create a machine account as follows: + +&rootprompt; smbldap-useradd.pl -w domain_name + +Then set the desired trust account password as shown here: + +&rootprompt; smbldap-passwd.pl domain_name\$ + +Using a text editor, create the following file: + +dn: uid=domain_name$,ou=People,dc={your-domain},dc={your-top-level-domain} +changetype: modify +sambaAcctFlags: [I ] + +Then apply the text file to the LDAP database as follows: + +&rootprompt; ldapmodify -x -h localhost \ + -D "cn=Manager,dc={your-domain},dc={your-top-level-domain}" \ + -W -f /path-to/foobar + +Create a single-sided trust under the NT4 Domain User Manager, then execute: + +&rootprompt; net rpc trustdom establish domain_name + + + + +It works with Samba-3 and NT4 Domains, and also with Samba-3 and Windows 200x ADS in mixed mode. +Both DC's, samba and NT, must have the same WINS server otherwise +the trust will never work. + + + + + + + -- cgit