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 protected] to [email protected] - 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[22.214.171.124]: Connection timed out (port 25) Jan 9 01:32:36 server1 postfix/smtp: 7656E7041AF: to=<[email protected]>, relay=none, delay=30, delays=0.06/0.01/30/0, dsn=4.4.1, status=deferred (connect to mxs.mail.ru[126.96.36.199]: Connection timed out) Please note that I can ping 188.8.131.52 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?