can telnet to smtp on localhost but not using domain name

[Guest_imported]

I have a problem where I can do a
'telnet localhost smtp'
and it works fine, but if I try to
'telnet mydomain smpt'
I get a 'connection refused message. This is
my first attempt at setting up sendmail under redhat 7.1.
Thanks

 

[feeble]

you have dns issues. you need to run named most likely. also make sure you have name servers in your resolv.conf. you machine is unable to resolv your dns name to the ip of your host.