Mail Server not receiving mails v.7.8.2003

System version: NethServer release 7.8.2003 (final)
Kernel release: 3.10.0-1062.18.1.el7.x86_64

I don’t know if it has anything to do with upgrading to version 7.8.2003, but no emails have been received for a few weeks. Emails can be sent from any account.

The router has active rules for routing ports 143,995,110 says:
DMARC Record found
DMARC Quarantine / Reject policy enabled
DNS Record found

If I give an email from for example :
Unable to deliver message after multiple retries, giving up.

1 Like

You’re missing at least 3-4 SMTP ports…

I said I can send emails so I haven’t written about smtp ports. Also email users can give / receive emails
between them.

If the RED interface of Nethserver has an private IP address, the ports for SMTP protocol must be forwarded, as far as i know.
The same if NethServer has only GREEN interface.

yes the port 25,465 is forwarded … but i can not receive emails from outside.
I have been using nethserver since 7.5.1804 and I did not have this problem

587 is missing. Do you allow your service to be contacted outside the LAN?

Which is your environment? Only Green? Green+Red? Green+Red+Router?

587 forwarded too …


Hi Stefan

For recieving e-mails from the Internet ONLY Port 25 is relevant.E-Mail between Servers on the Internet is always sent to the recipients Port 25.

Ports 465 (SSL) and 587 (Submission) are ONLY used by clients sending mails. NethServer can handle clients mail (With Authentification) also on Port 25 (Using TLS).

What could be possible, is that your provider is now (not earlier) blocking Port 25. A lot of providers globally do this for consumer / residential Internet connections.
These provider people, by their thinking, a consumer will NEVER have a full blown mail server at home… So they block incoming and sometimes also outgoing port 25, to reduce spam.

You can check this, if you can test from your mobile (With 4G) as hotspot to your Notebook.
Use a command window, and use:

telnet my-home-servers-IP 25

This command will work for ANY mailserver. The server will answer with it’s version and capabilities, depending on the software running mail.

If this works, then you know it’s NOT your provider blocking you!

Note: I can also do the test for you - the Internet IS global! Or anyone else, a friend or someone you know. You’ld just need to pass your momentary external IP to test. (PM)

My 2 cents

1.telnet 25
220 ESMTP Postfix

250-SIZE 20000000
250 DSN

  1. mail from:
    250 2.1.0 Ok

  2. rcpt to:
    554 5.7.1 [] Relay access denied

Hi Stefan

Try these here:

Yes, even Microsoft suggests using telnet to test / diagnose Mail!


This here seems to indicate a mail relay, maybe part of the problem?

Good Luck

@evrika do you have Fail2ban or Clamav installed?
Is SMTP Proxy module installed?


I suspect that for telnet tests both advanced options must be checked

No, those options only serve to accept smtp connections on trusted networks (green)

Some relevant messages in /var/log/maillog ?

Check for all mailboxes whether that item is ticked or not:

Having same problem here- SMTP obviously not working. POP is turned off in our config.
So Mail Traffic normaly working over imap and smtp, while imap works smtp stopped working since last update.

I don´t know if it´s the same Problem, but push massages from Mattermost are also not working since that update- so probably a Intrusion detection, Failban or Firewall issue.

Or rSpamD…


I don’t think the problem is with NethServer.
An analysis made with appears in the SMTP test:

  • SMTP Reverse DNS Mismatch / Reverse DNS does not match SMTP Banner
    So in the DNS1 server that refers to DNS2 (where the email server is) I can’t enter the IP record PTR for the email server but it is entered in Reverse Lookup Zones in DNS2.