I'm running a CentOS 5.4 machine and had trouble getting sendmail to work. After a bunch of researching, I found out that I needed to change my servers FQDN.
/etc/hosts had the following:
127.0.0.1 localhost localhost.localdomain xx.xx.xx.xx test
(the xx.xx.xx.xx is my server's real IP address, and 'test' is I believe the name of the machine)
I removed the above two lines and replaced it with:
xx.xx.xx.xx mydomain.com MyDomain
sendmail now works perfectly, but because I'm inexperienced with Linux and FQDNs, I'm not sure if changing this file will cause unexpected problems somewhere else. Web and FTP access seem unaffected, but I'm curious if any Linux gurus know if I did something wrong.
Thanks in advance!