I have a situation when forwarding from postfix mail server to yahoo,gmail,aol,icloud and many others forwarded email delivery to major ESP stopped at once though it works for my company email and the emails that are not being forwarded like if i send direct email to gmail or yahoo or one of the ESP that are not working with forwarding. The telnet is working and trace route is also working fine to the IPs of the email servers that are blocking forwarded emails. What about forwarded email could be different?

In mail Queue

May 10 09:36:43 apollo postfix/smtp[18975]: connect to alt1.gmail-smtp-in.l.google.com[]:25: Connection timed out
May 10 09:36:56 apollo postfix/smtp[18971]: connect to alt1.gmail-smtp-in.l.google.com[]:25: Connection timed out
May 10 09:44:25 apollo postfix/smtp[21829]: connect to alt1.gmail-smtp-in.l.google.com[]:25: Connection timed out

telnet 25

Connected to
Escape character is '^]'.
220 mx.google.com ESMTP m7si2343689eeu.50 - gsmtp

Trace Route

traceroute -n 
traceroute to (, 30 hops max, 60 byte packets
 1  10.908 ms  10.796 ms  6.024 ms
 2  154.689 ms  154.571 ms  154.534 ms
 3  10.415 ms  5.663 ms  9.353 ms
 4  9.425 ms  9.443 ms  9.997 ms
 5  9.508 ms  9.274 ms  9.397 ms
 6  24.312 ms  18.781 ms  18.532 ms
 7  31.088 ms  5.474 ms  5.020 ms
 8  21.222 ms  4.794 ms  4.244 ms
 9  10.956 ms  10.844 ms  10.491 ms
 10  114.587 ms  17.799 ms  17.341 ms
 11  118.049 ms  117.776 ms  120.510 ms
 12  * * *
 13  36.807 ms  36.536 ms  44.576 ms

What could be the reason when forward mail is in the queue, it gets connection timeout and rest of the emails are working fine. How postfix handles the forwarded emails?

  • Maybe you are sending too many emails at one time? – NickW May 10 '13 at 13:10
  • There is one email that is supposed to be forwarded when source email address receives and email mail queue is no more than 300 that has connection time out issues and all of those emails are deferred because of connection time out issue and they are forwarded emails. What do you mean by sending many email at one time. – user2352819 May 10 '13 at 16:28
  • Many providers will block servers sending hundreds of mail at a time.. if your server tries to send them all at once, it may cause them to temporarily limit the amount of connections you can make to that IP. I'm only guessing here, there is no reason why postfix itself would do so, unless you have some of the options in here set up : postfix.org/TUNING_README.html – NickW May 10 '13 at 16:35

It had nothing to do with the Postfix. It was firewall blocking the postfix user to communicate with port 25.

The csf has SMTP BLOCK configuration and that configuration was messed up. As postfix runs with with the postfix user, the csf had made root user owner of the port 25 so no user other than root could sent the emails but forwarded emails were being sent as postfix user. So adding postfix to the port 25 owners, the issue was resolved.

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