Setting up RFC2307 in AD

Introduction

RFC 2307 defines the possibility to store user and group information in an LDAP directory. In an Active Directory (AD) with Linux integration, this has several advantages:

• Central administration of IDs in AD.
• Consistent IDs on all Linux domain members that use the Samba idmap_ad ID map back end.
• Fast configuration of attributes.
• No local ID mapping databases that can corrupt and thus cause lossing file ownerships.
• Enable the administrator to set individual login shells and home directory paths for users.
• Login shell and home directory settings are the same on all domain members using Samba idmap_ad ID map back end and winbind nss info = rfc2307 parameter.
• Easy management from Windows clients using the Active Directory Users and Computers (ADUC) Microsoft management console (MMC). For details, see Maintaining Unix Attributes in AD using ADUC.

Verifying the Domain Controller and Active Directory Setup

Run the following tests to verify if the RFC2307 integration is already enabled in your Active Directory (AD):

RFC2307 on AD Domain Controllers

On a AD DC there should not be more than the sysvol and netlogon share, so the usage of unified RFC2307 idmappings is not really important. If you want to enable RFC2307 ID mappings on the DC for whatever reason, the you would have to verify on the Samba DC, that the idmap_ldb:use rfc2307 parameter exists and is set to yes in the [global] section of your smb.conf file:

 idmap_ldb:use rfc2307 = yes

It is recommended not to use those mappings on the DCs. The default idmap ldb mechanism is fine for domain controllers and less error prone.

Verifying That the NIS Extensions Are Installed in Active Directory

Verify that the ypServ30 LDAP tree exists in your Active Directory (AD):

ldbsearch -H /usr/local/samba/private/sam.ldb -s base -b CN=ypservers,CN=ypServ30,CN=RpcServices,CN=System,DC=samdom,DC=example,DC=com cn
# record 1
dn: CN=ypservers,CN=ypServ30,CN=RpcServices,CN=System,DC=samdom,DC=example,DC=com
cn: ypservers

# returned 1 records
# 1 entries
# 0 referrals

If the ldbsearch command returns 1 record, the NIS Extensions are installed.

Setting up RFC2307 and NIS Extensions in a Samba AD

Provisioning a New Samba Active Directory with RFC2307 Enabled

When you provision a new Samba AD forest, pass the --use-rfc2307 to the samba-tool domain provision command to auto-install the NIS extensions. For example:

# samba-tool domain provision --use-rfc2307 ...

For details, see Provisioning a Samba Active Directory.

Additionally, enable the the Samba RFC2307 module. For details, see Enabling the RFC2307 Configuration Parameter.

Installing the NIS Extensions

Do not run this procedure if you provisioned your Active Directory (AD) with the --use-rfc2307 parameter. For details, see Provisioning a New Samba Active Directory with RFC2307 Enabled.

Updating the Schema can break your AD. Verify you have a working backup before updating the schema.

To install the NIS extensions:

• Locate the domain controller (DC) with the Schema Master flexible single-master operations (FSMO) role:

# samba-tool fsmo show | grep SchemaMasterRole
SchemaMasterRole owner: CN=NTDS Settings,CN=DC1,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,DC=samdom,DC=example,DC=com

The output shows the name of the DC owning this role. Run all further steps on this DC.

• Shut down the Samba service.

• Create a copy of the ypServ30.ldif schema file. For example:

# cp /usr/local/samba/share/setup/ypServ30.ldif /tmp/

• Replace the variables in copied LDIF file with the domain distinguished name (DN), NetBIOS name, and the NIS domain of your setup. For example:

• ${DOMAINDN}: DC=samdom,DC=example,DC=com
• ${NETBIOSNAME}: DC1
• ${NISDOMAIN}: samdom

# sed -i -e 's/${DOMAINDN}/DC=samdom,DC=example,DC=com/g' \
         -e 's/${NETBIOSNAME}/DC1/g' \
         -e 's/${NISDOMAIN}/samdom/g' \
         /tmp/ypServ30.ldif

• Import the modified LDIF file to the local /usr/local/samba/private/sam.ldb Samba AD database:

# ldbmodify -H /usr/local/samba/private/sam.ldb /tmp/ypServ30.ldif --option="dsdb:schema update allowed"=true
Modified 55 records successfully

• Start the Samba service.

The AD replicates the updated schema to all DCs in the forest.

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