I am trying to setup postfix to get emails. Using this tutorial I have configured everything but it still doesn't work. When trying to telnet locally, there seems to be a wrong hostname when greeted with HELO message. It looks like this: Code: [email protected]:~# telnet localhost 25 Trying ::1... Trying 127.0.0.1... Connected to localhost. Escape character is '^]'. 220 example.com ESMTP Sendmail 8.14.3/8.14.3/Debian-9.4; Mon, 22 Jul 2013 18:24:11 +0300; (No UCE/UBE) logging access from: localhost.localdomain(OK)-localhost.localdomain [127.0.0.1] What could cause this and what should I check first? I googled maybe for an hour or two, but nothing seems to be working!