I have a CentOS installation with bind/postfix/dovecot. After I installed it I tested and I could send emails to any direction without problems. After some time (maybe a month or so) when I tried to send an email I noticed that it wasn't delivered to destination. When I checked the logs I found something like this:
postfix/smtp ... host alt1.gmail-smtp-in.l.google.com[220.127.116.11] refused to talk to me: 451 too many connection attempts ... postfix/smtp: 2EFC411083A7: to=<email_here>, relay=none, delay=120, delays=0.02/0.01/120/0, dsn=4.4.1, status=deferred (connect to alt4.gmail-smtp-in.l.google.com[18.104.22.168]: Connection timed out)
It does get sent to some small mail services but not to major like gmail yahoo or hotmail. The issue is the same above. I googled a lot for this error but found nothing that would solve this.
It does happen on CentOS 5.5, postfix 2.3.3
Does anyone know how to fix it?
UPDATE: Everybody tries to tell me that I send too many emails. This is not the case. I wasn't sending any email from this server. I just installed it, configured, tested, and forgot about it. Just used to develop web applications on it. And no, there isn't any web application on it through which somebody could send tons of emails. And I checked the logs and there aren't any email sent from this server. So the problem is not that I or somebody else used this server to spam or to send tons of email.