We have several Linux servers that authenticate Linux user passwords on our Windows Active Directory Server using PAM and Kerberos 5. The Linux distro we use is CentOS 6.
On one system, we have several Version Control Systems like CVS and Subversion, both of which authenticate users throug PAM, such that users can use their normal Unix resp. Windows AD accounts.
Since we started using Kerberos for password authentication, we experienced that CVS on a client machine is often much slower in establishing a connection. CVS authenticates the user on every request (eg. cvs diff, log, update...).
Is is possible to cache the credentials that kerberos uses, sucht that is does not need to ask the Windows AD server every time a user executes a cvs action?
Our PAM config /etc/pam.d/system-auth looks like the following:
auth required pam_env.so auth sufficient pam_unix.so nullok try_first_pass auth requisite pam_succeed_if.so uid >= 500 quiet auth sufficient pam_krb5.so use_first_pass auth required pam_deny.so account required pam_unix.so broken_shadow account sufficient pam_succeed_if.so uid < 500 quiet account [default=bad success=ok user_unknown=ignore] pam_krb5.so account required pam_permit.so password requisite pam_cracklib.so try_first_pass retry=3 password sufficient pam_unix.so md5 shadow nullok try_first_pass use_authtok password sufficient pam_krb5.so use_authtok password required pam_deny.so session optional pam_keyinit.so revoke session required pam_limits.so session [success=1 default=ignore] pam_succeed_if.so service in crond quiet use_uid session required pam_unix.so session optional pam_krb5.so 
