Problem:
On rare occasions it has been seen by Centrify Support that problems installing Centrify DirectControl can occur. In this example it was found that shortly after running the install.sh script, the following error message was seen:

./install.sh: line 3630: 12649 Segmentation fault
WARNING: Centrify adcheck exited with error(s).







Cause:
When using the GDB tool to examine the core dump file created from the segmentation fault error, it was discovered that the following setting in the /etc/krb5.conf was contributing to the issue: 

dns_lookup_realm = true 

Normally, before adjoin there should be a stock (sample) krb5.conf file which does not have the default_realm nor dns_lookup_realm set. 

After adjoin, adclient will update the krb5.conf, so it will have a valid default_realm and a valid dns_lookup_realm set. 

The problem occurs when before adjoin, there is a krb5.conf that does not have the default_realm set but does have the dns_lookup_realm set. This combination triggers a sequence of events inside the kerberos libraries with Centrify's hook that ends up in a DNS lookup loop. 


Solution:
In the /etc/ directory, check to see if the krb5.conf.pre_cdc file exists. If so, rename it to krb5.conf and then rerun the install.sh script.



More about using the GDB debugging tool can be found here:
https://centrify.force.com/support/Article/KB-1634-How-to-analyze-core-dump-using-GDB-DBX-MDB-debugger