[Sunhelp] Sendmail

[Ian Flavin]

Right, 
I know this is going to be a very general query, but I'll give it a shot
anyway.  When trying to send amil from a Sol. 7 Machine, the user keeps
getting a 550 error back (Host unkown).  He can receive mail to that
box, and send mail to users within the domnain, but when he trys to send
a messange outside to Internet, he gets this error.  Any clues would be
greatly apprieciated.