Configure Port 2525

peterbata

Hello. First off, I would like to take this opportunity to wish the entire Mailcow family all the best in 2024.
I setup Mailcow for the first time in a docker environment today. Prior to my moving over to Mailcow I had been successfully using HestiaCP for both web and mail hosting in my homelab.

The Mailcow basic setup apprears to be fairly straightforward. I made sure to forward all relevant ports at my router. I should mention that in order for me to send / receive mail I have to use two different providers. Dynu and SMTP2GO.

I should also mention that DNS is setup in Cloudflare.
My ISP blocks port 25.

Here is what I have done so far. Please correct me if I am not on the right track:

I configured SMTP2Go in the Routing / Add sender-dependent transport (See attached screenshot)
I am able to send mail from the builtin mail client (SoGo)

Here is where I am a little confused.
In the Options / Fowarding Hosts I entered relay.dynu.com
Once I clicked on Add+ the Dynu IP addresses were automatically populated in the upper section.
However, when I respond to the mail that I send from one of my domain mailboxes it is never received.

The two Dynu services that I use and have used for a number of years are
1) Email Store/Forward
2) SMTP Outbound Relay (this service requires that I use their SMTP host name / a username and password

[https://i.postimg.cc/yxs1gpy5/MC-Add-sender-dependent-transport.jpg](https://)
[https://i.postimg.cc/HW9sDHpC/MC-Forwarding-Hosts.jpg](https://)
[https://i.postimg.cc/NMwYSCSM/Dynu-Email-Store-Forward.jpg](https://)
[https://i.postimg.cc/NMwYSCSM/Dynu-Email-Store-Forward.jpg](https://)

Your time, patience, and assistance will be greatly appreciated. Peter

esackbauer

I have a similar setup, but because I want to avoid 3rd parties to read my mails as few as possible I do not use a service like Dynu. Even with my “dynamic” IP I can receive on port 25 without any problems.

For sending I use a service like smtp2go like you.
Make sure that for every(!) domain you have configured, it uses the sender dependent transport.

peterbata However, when I respond to the mail that I send from one of my domain mailboxes it is never received.

So you are responding via a mailbox outside of mailcow? Do you get a bounce message in that mailbox?
Have you checked your postfix logs?

peterbata

esackbauer Thank you so much for your prompt reply. Kindly explain how it is that you can still receive mail if your ISP blocks port 25. I would greatly appreciate that

esackbauer If I send a message from one of the email accounts that I have setup in Mailcow (peter@mydomain.com) to a Gmail account for example. I then respond to the received email. However, the Mailcow account never receives it.

esackbauer

peterbata if your ISP blocks port 25.

My ISP blocks only outgoing, not incoming.
You should really consider a proper hosting then. It gets more and more diffucult and unreliable the more tools are in the chain. And running a mail server on a dynamic IP is of course not supported by mailcow.

peterbata However, the Mailcow account never receives it.

Check your TLSA records. Last time someone had this problem the TLSA record did not match the domain/LE certificates.

peterbata

esackbauer Thank you again. As I stated in an earlier reply my ISP blocks both incoming and outgoing on port 25. My IP is static. I have had absolutely no issues sending / receiving when using HestiaCP which in my opinion is very user friendly and a breeze to setup. I am not implying that Mailcow is not as I am not as familiar with it, yet!