Help setting up email with Open-Xchange

First post on this forum and first-time cloud server manager. Not an IT professional by trade, so please take that into consideration while reading.

I was trying to setup a mailing server for my company on my UCS server with OpenXchange. I got the Open-Xchange part working for the cloud stuff, storage and collaborative documents all work fine, and I can also send emails from the server to an external address without issue and with the correct domain extension. So all of that works just fine.

The problem is when I go to send mail from an external address to the server, the mail never arrives. I have tried to look into putting an MX record in with my domain provider (GoDaddy) but after several combinations of that, along with A records, I still am not able to get the mail to send across. I am not sure where to go from here, I have exhausted all of what I can think of on google to search for an answer to this.

Any help would be greatly appreciated. Thank you so much in advance!

I am still looking for assistance with this. No one has reached out about this yet and I have tried several other things. Still can send email out from the UCS server, but it never arrives when sent from the outside. This tells me it’s a thing with the MX records in my Domain hoster. I have set the MX record to forward to my IP, but I still do not get anything in.

Looking forward to any help on this. Thank you.

Usually emails will not get lost, in case of a misconfiguration you will get a bounce message. This message will contain useful hints about the problem. In case you do not get such notifications the message is delivered somewhere. The question is: where?
There should be an explanation how to configure MX records at GoDaddys, in general it needs an A record to point to. This means that your UCS needs to have an A record in the public DNS as well.
It is not possible to tell anything whether your MX-configuration is vaild or without further details.

There might be configuration problems on UCS which would for example result into an issue that the message is accepted by the system but not delivered to the local mailbox. Google will not know whats wrong, but looking at the logs, especially at /var/log/mail.log could shed some light on the problem.

Thank you for the reply!

Yes, I do get a message undeliverable return email on the outside mailbox after about 4 or 5 days. I understand the concept of the A record and MX record. I have it setup like that, where the A record is pointing to my IP and then the MX record is pointing to that address. However, I am unsure of what the proper formats for the MX record should be. For instance, I just have it set as “” and then the A record is “mail” pointed to my public IP. I also have ports 27, 110, 143, 465, 587, 993-995, and 2525 forwarded. My ISP purposely blocks port 25, so I do not have that one open.

Is there something I am missing on my end here?

Also, there is nothing relevant in this file, just some notes I see about internal mail being sent back and forth.

“The world” will not know that SMTP for your domain is not listening on port 25 as usual. Every other mailserver will try to deliver on that port and I expect this or something similar to be mentioned in the bounce message.
I fear that you can not get mails this way. In that case I’d try to

  • consider using some cheap POP3-mailbox service together with Fetchmail (already included in OX, see OX-Mail module)
  • use some configurable mail forwarding service which allows delivery on custom ports (dont know if this exists)
  • change the ISP

I am using option 1 for my private domain.


So it is Port 25, I figured that would be the issue from the beginning.

I will take a look into the FetchMail as the other two suggestions are unknown possibility for the changing of ports, or completely impossible for changing ISP, only one service provider in my area, and they are pretty terrible.

I really appreciate the help. If there is any additional stuff I run into, then I can see about posting it to this thread or opening another.

Thank you again!

So I looked into this more, and the email protocol says that port 25 is used for outgoing emails, but port 465 can as well, which I am able to use. I can get emails that I send from my server, I cant get ones sent from the outside into my server. So I think the idea that the problem is port 25 is incorrect on further investigation.

I am pretty convinced that I never setup the MX records right inside of my domain provider still. I literally had one random one, that I just took a shot in the dark at as there was no real setup.

Trying this at a different angle, where is the documentation for setting the MX records, assuming that ports are not an issue, since that would need to be set either way.

Thank you!

Server-side SMTP is Port 25, SMTPS(465) or Submission (587) is commonly used for outgoing mail.
se also:

MX records are defined at the place where the DNS zone is administered. The documentation at appears to be descriptive. In some rare cases the external representation of DNS-data is provided by UCS and applies.