Postfix can't send mails externally

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

nc -z 25

If it does not output Connection to 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!

Hello there,

It’s possible that port 25 is closed for external uses for new accounts. There are a few ways to go about the problem

  • try using ports like 465 or 587 for SMTP
  • use a third-party solution only for your E-mails. Good examples are SendGrid.

To expand more on blocking port 25 for new accounts, this is something DigitalOcean has been doing to reduce spam on its network. It is more that we simply cannot accurately determine who is going to send it.

Stopping spam is a constant fight, so DigitalOcean has implemented some restrictions on newer accounts. Having said that, you can always contact them and ask for the port block to be lifted on:

More information here:

Hope that helps!

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