==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release): 1.5.1
- Deployed with iRedMail Easy or the downloadable installer? installer
- Linux/BSD distribution name and version: Ubuntu 20.04 LTS
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): MariaDB
- Web server (Apache or Nginx):Nginx
- Manage mail accounts with iRedAdmin-Pro? NO
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====

Hi,

I've been trouble shooting this problem all day and have got nowhere so i'm throwing out to the experts.

I have a freshly setup iRedmail machine in the DMZ of an IPFire firewall with relevant rules opening the various ports as recommended in iRedMails documents. All the A, MX and other pointers are set up correctly as well.

Sending mail works fine, but I cannot receive any mail - the mail always returns with

'smtp; 400 Network error: Could not connect to mydomain:25'

So i've scratched my head and tested from outside using a port scanner and it says port 25 is open - i've used telnet to connect to the port and it replies as expected.

So then I moved the machine from behind the firewall and set it's ip to the public ip and tried again with the same results.....

I even disbaled UFW to see if that was causing my issue.

I had a squiz at the logs and i can see outgoing mail and the external telnet connections but nothing for external incomming mail.

What am i missing ? Any pointers or clues gratetfully accepted.

cheers