9.8. Verifying the trust configuration on AD

Procedure

1. On the AD server, set the nslookup.exe utility to look up service records.

   C:\>nslookup.exe
   > set type=SRV

2. Enter the domain name for the Kerberos over UDP and LDAP over TCP service records.

   > _kerberos._udp.idm.example.com.
   _kerberos._udp.idm.example.com.       SRV service location:
       priority                = 0
       weight                  = 100
       port                    = 88
       svr hostname   = server.idm.example.com
   > _ldap._tcp.idm.example.com
   _ldap._tcp.idm.example.com       SRV service location:
       priority                = 0
       weight                  = 100
       port                    = 389
       svr hostname   = server.idm.example.com

3. Change the service type to TXT and run a DNS query for the TXT record with the IdM Kerberos realm name.

   C:\>nslookup.exe
   > set type=TXT
   > _kerberos.idm.example.com.
   _kerberos.idm.example.com.        text =
   
       "IDM.EXAMPLE.COM"

4. Run a DNS query for the MS DC Kerberos over UDP and LDAP over TCP service records.

   C:\>nslookup.exe
   > set type=SRV
   > _kerberos._udp.dc._msdcs.idm.example.com.
   _kerberos._udp.dc._msdcs.idm.example.com.        SRV service location:
       priority = 0
       weight = 100
       port = 88
       svr hostname = server.idm.example.com
   > _ldap._tcp.dc._msdcs.idm.example.com.
   _ldap._tcp.dc._msdcs.idm.example.com.        SRV service location:
       priority = 0
       weight = 100
       port = 389
       svr hostname = server.idm.example.com

   Active Directory only expects to discover domain controllers that can respond to AD-specific protocol requests, such as other AD domain controllers and IdM trust controllers. Use the ipa-adtrust-install tool to promote an IdM server to a trust controller, and you can verify which servers are trust controllers with the ipa server-role-find --role 'AD trust controller' command.

5. Verify that AD services are resolvable from the AD server.

   C:\>nslookup.exe
   > set type=SRV

6. Enter the domain name for the Kerberos over UDP and LDAP over TCP service records.

   > _kerberos._udp.dc._msdcs.ad.example.com.
   _kerberos._udp.dc._msdcs.ad.example.com. 	SRV service location:
       priority = 0
       weight = 100
       port = 88
       svr hostname = addc1.ad.example.com
   > _ldap._tcp.dc._msdcs.ad.example.com.
   _ldap._tcp.dc._msdcs.ad.example.com. 	SRV service location:
       priority = 0
       weight = 100
       port = 389
       svr hostname = addc1.ad.example.com