I am seeing ntlm_auth taking too much time in my couple of freeradius server lately, I am pretty much sure this is because of "BILL GATES" AD responding slow.

Dec 15 22:51:16 radserver1radiusd[1884]: Child PID 3300 (/usr/bin/ntlm_auth) is taking too much time: forcing failure and killing child.
Dec 15 22:51:20 radserver1 radiusd[1884]: Child PID 3302 (/usr/bin/ntlm_auth) is taking too much time: forcing failure and killing child.
Dec 15 22:51:21 radserver1 radiusd[1884]: Child PID 3303 (/usr/bin/ntlm_auth) is taking too much time: forcing failure and killing child.

Here are my Versions:
samba-winbind-3.6.23-12.el6.x86_64
freeradius-2.1.12-6.el6.x86_64