To manually specify a domain controller, add the following entry to the Centrify configuration file, /etc/centrifydc/centrifydc.conf:
dns.dc.domain_name: server_name [server_name ...]
For example, if you want to ensure the Centrify Agent uses the domain mylab.test and the domain controller named dc1.mylab.test, you could add the following line to the /etc/centrifydc/centrifydc.conf file:
Note: You must specify the name of the domain controller, not its IP address. In addition, the domain controller name must be resolvable using either DNS or in the local /etc/hosts file. Therefore, you must add entries to the local /etc/hosts for each domain controller you want to use if you are not using DNS or if the DNS server cannot locate your domain controllers.
To specify multiple servers for a domain, use a space to separate the domain controller server names. For example:
dns.dc.mylab.test: dc1.mylab.test dc2.mylab.test
The Centrify Agent will attempt to connect to the domain controllers in the order specified. For example, if the domain controller dc1.mylab.test cannot be reached, the agent will then attempt to connect to dc2.mylab.test.
If the global catalog for a given domain is on a different domain controller, you can add a separate dns.gc.domain_name entry to the configuration file to specify the location of the global catalog. For example:
You can add as many domain and domain controller entries to the Centrify configuration file as you need. Because the entries manually specified in the configuration file override any site settings for your domain, you can completely control the Centrify Agent for *NIX’s binding to the domains in your forest through this mechanism.
Note: In most cases, you should use DNS whenever possible to locate your domain controllers. Using DNS ensures that any changes to the domain topology are handled automatically through the DNS lookups. The settings in the configuration file provide a manual alternative to looking up information through DNS for those cases when using DNS is not possible. If you use the manually-defined entries in the configuration file and the domain topology is changed by an Active Directory administrator, you must manually update the location of the domains in each configuration file.
Using the fixdns script
The Centrify Agent includes a fixdns script that you can use to inspect your environment and make the necessary configuration file changes for you.
To run this script, you need to specify the domain controller name and IP address:
fixdns domain_controller_name IP_address
For example if you intend to join the domain mytest.lab and the domain controller for that domain is dc1.mytest.lab and its address is 172.27.20.1, you would run the following command:
fixdns dc1.mytest.lab 127.27.20.1
The fixdns script will then make the necessary changes to the /etc/hosts and the Centrify configuration file.
Note: This script does not update the /etc/resolv.conf file. If the script cannot locate the domain controller using the existing /etc/resolv.conf settings, it will assume that you want to use settings from the configuration file.