Code: Dec 28 11:56:58 debian postfix/smtpd[19337]: connect from localhost.localdomain[127.0.0.1] Dec 28 11:56:58 debian postfix/smtpd[19337]: 665F14D00FE: client=localhost.localdomain[127.0.0.1] Dec 28 11:56:58 debian postfix/cleanup[19342]: 665F14D00FE: message-id=<[email protected]> Dec 28 11:56:59 debian postfix/qmgr[7733]: 665F14D00FE: from=<[email protected]>, size=1943, nrcpt=1 (queue active) Dec 28 11:56:59 debian postfix/smtpd[19337]: disconnect from localhost.localdomain[127.0.0.1] Dec 28 11:57:00 debian postfix/smtp[19343]: 665F14D00FE: to=<[email protected]>, relay=gmail-smtp-in.l.google.com[216.239.59.27]:25, delay=2.7, delays=0.51/0.02/0.36/1.8, dsn=2.0.0, status=sent (250 2.0.0 OK 1230466189 t2si16460221gve.19) Dec 28 11:57:00 debian postfix/qmgr[7733]: 665F14D00FE: removed Above is the code from the mail logs stored after sending an email. If you have a look at it carefully it says client is localhost.localdomain[127.0.0.1] which I want to replace with mysite.com. I have added mysite.org to /etc/hosts before localhost.localdomain. And hostname -f gives ,mysite.org; but still the client in the message header remains same as localhost.localhomain. What to do? I have postfix configured