Question

Postfix can't send mails externally

Posted September 6, 2017 3.5k views
Security DigitalOcean Applications Ubuntu 16.04

Hi everyone,

I installed and configure on Ubuntu 16.04 droplet but it couldn’t send email externally.

I’ve tested this scenarios:

  • Send an internal emails, it works.
  • send an email from gmail or yahoo mail or other email service, it works too, so I receive the email in the appropriate mailbox.

The unique scenario that doesn’t work is when i try to send to an external email services such as google, yahoo, outlook or other site.

Looking into the Postfix logs I got the some different error messages:
a. Network is unreachable
b. Connetion timeout

Could you please help me? I already opened a ticket for looking into this issue (ports configuration and droplet exceptions) but I didn’t receive any feedback/new about the solution… so I’m considering change my VPS cloud provider.

Could you recommend me any other VPS Could server provider?

Thank you all your help.

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3 answers

Hi! Can you please post the output of the following command?

nc -z smtp.gmail.com 25

If it does not output Connection to smtp.gmail.com port 25 [tcp/smtp] succeeded!, it’s possible that outbound SMTP is blocked on your droplet. In that case, the support team will be able to unblock it for you!

Hi, I’m facing the same issue, but on a Centos7:

Feb 13 18:18:38 xxx postfix/smtp[28162]: 71259434AFB: to=<xxx@yahoo.com.br>, relay=none, delay=150, delays=0.06/0.03/150/0, dsn=4.4.1, status=deferred (connect to mta5.am0.yahoodns.net[98.136.102.54]:25: Connection timed out)

Feb 13 16:34:09 xxx postfix/smtp[27606]: connect to gmail-smtp-in.l.google.com[74.125.192.26]:25: Connection timed out

All my Outbound rules are allowed… Can you help?

Btw, running nc -z smtp.gmail.com 25 takes a while and response is empty

I am facing the same problem. I run nc ... and no output…

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