Originally Posted by falko
myhostname = mydomain.com
Are you using mydomain.com for a web site as well?
I recommend to buy a "technical" domain, i.e., a domain that you use only for naming your servers and not for email, web sites, etc. You'd then use this domain for myhostname and mydomain in /etc/postfix/main.cf.
Yes, mydomain.com is used for a web site as well. Besides purchasing a separate domain, is there any other solution? I tried setting mydomain and myhostname to any of the two domain on this machine (all with websites) and none of them worked. Does using a subdomain like themachine.mydomain.com work?
BTW, what are mydomain and myhostname used for? I tried setting them to invalid domains, and nothing seemed to break (and this problem wasn't fixed of course.)