Using RedHat Enterprise Linux at work, one of the things I have had to do is edit my hosts file in /etc/hosts.
The problem I started having was that my hosts file kept getting re-written over with a default file, so any changes I made disappeared.
Eventually after going through various hosts* files, I noticed there was a non-standard file in there called hosts.ac. Turns out, this is a hosts file that is created by Cisco’s AnyConnect and whatever is in this file rewrites my hosts file.
The quick fix? Make all the hosts file changes to the hosts.ac file. That way, it is copied over to the hosts file. The “true” fix.. well, I am still working on that one.
I even deleted the hosts.ac file and tried renaming it. But, nonetheless, if the Cisco AnyConnect program is restarted (it doesnt even have to connect, just restarted) it will rebuild the hosts.ac file yet again and you are back to square 1.
So for now, just edit the hosts.ac file and it will copy over to the hosts file.
*update*
Looking through /var/log/messages I did notice that there is a service I am curious about when starting up Cisco AC
acvpnui