[CentOS] sudo doing DNS lookup

From: Steve Clark <sclark at netwolves.com>
>I have a confusing problem. I have two centos 5,5 boxes. Both have
>sudo.i386                                1.7.2p1-9.el5_5               
installed
>I am using the same sudoers file, but the one on box A keeps trying to do DNS 
>lookups
>while the one on box B does not. How do I disable this DNS lookup?

Do you have fqdn in sudoers?

man sudoers:
"Beware that turning on fqdn requires sudo to make DNS
 lookups which may make sudo unusable if DNS stops
 working"

JD