Does your "sudo " hang on Centos/Fedora/RHEL/Debian ? mine does too

Warning: this is for google to index this and help out other poor hapless souls.

If your sudo adduser/passwd/vim , etc. are hanging on any of the Redhat distro variants - its because of this not-a-bug. Apparently, Redhat does a DNS lookup whenever you do a sudo.

This usually happens when you change the hostname incorrectly. The way to fix it is to fix your /etc/sysconfig/network