I'm a new Linux user and am having a problem with sendmail 8.12.8. I'm running Redhat 9 on a machine connected to the outside world through a campus network jack. Everything was working fine until I changed the name of my Linux box in the /etc/hosts file. Now mesages sent to any user at my machines address get redirected to the root for the campus network.

I was told make sure my sendmail.cf file was a "null client" but have been unsure as to how to do that. I was also told to define an alias for root to go to me so that my root email doesn't get redirected to the main systems administrator. Is there an easy explanation for how these things could be accomplished? Thanks in advance and sorry for what I'm sure are very simple questions.