I know there's a lot of posts on this forum about postfix, but I haven't found the answer... The problem is that I can't send emails to any external e-mail address (I'm using ISPConfig - the perfect setup on Debian Etch). However, I can receive all emails and I can successfully send emails locally (for example, from email@example.com to firstname.lastname@example.org - when the domain.com is hosted on my ISPConfig server) This is what I get in the mail.log when I try to send to an external e-mail address: Jan 9 01:32:36 server1 postfix/smtp: connect to mxs.mail.ru[188.8.131.52]: Connection timed out (port 25) Jan 9 01:32:36 server1 postfix/smtp: 7656E7041AF: to=<email@example.com>, relay=none, delay=30, delays=0.06/0.01/30/0, dsn=4.4.1, status=deferred (connect to mxs.mail.ru[184.108.40.206]: Connection timed out) Please note that I can ping 220.127.116.11 from the server Port 25 is not blocked. Actually, the problem started when I changed the ISP (naturally I had to change the IP addresses everywhere, and everything works except for sending mails). Any ideas? Please?