Outlook the activesync on internal ip address

Good evening,
inter Outlook function Activesync for me only with the political static IP address. I added an alias (mail.domain.it) and can also remove it under nslookup. How can I remove activesync from the internal IP address (
With the Iphone it works with the internal IP.


Anmerkung 2020-07-22 000522 Anmerkung 2020-07-22 001947

I tested with Outlook 2016 and for using the internal IP I needed to allow it, maybe you need to recreate the account in Outlook.


Dear Mr. Neuberger,
thanks for the message. Unfortunately I have tried no change. If I enter nethserver.domaine.local into Outlook (email server) it works. As soon as I enter the alias mail.domaine.it, Sogo pushes to the external IP address, why?

Does it work if you enter the internal IP address instead of domain name?

If it works with external name, why do you want to use the internal name?

it works if I enter the server ip and the server hostname (nethserver.domaine.local.

Once I got the alias subdomaine (mail.domaine.it)
which is aimed at my external ip
Specify it only works on the iPhone but not under Outlook

Sorry, I don’t get it.
The internal IP/internal hostname works in Outlook but you want to use the public IP/public hostname?

Do you use portforwarding from a router to your Nethserver? In this case you may need to enable hairpin NAT to use the public IP/name.

Hello Mr. Neuberger,

thanks for the reply. I will explain it to you again. I have a subdomain on my static external ipaddress (mail.domain.it) Of course I forwarded the port.
I set up the server with nethserver.domain.local. I created an alias for this (mail.domain.it)
As soon as I enter the ipaddress of the server or the hostname nethserver.domain.local under Outlook server settings, Sogo pushes onto the internal network.
But if I specify the subdomain alias under Outlook server settings (mail.domain.it) everything also works. Sogo always pushes to the external IP address!!

Anmerkung 2020-07-22 231008

Now I figured it out myself. I installed the AVG anti-virus program a few days ago and Option Fake Website Protection triggered this problem. As soon as I deactivate this option, Sogo syncs again normally.

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Thanks for explaining but I cannot reproduce it. Which Outlook version do you use? Did you try to enable hairpin NAT?

If I set an alias and setup Outlook 2016 to use it as EAS server, it uses internal IP:


Jul 22 23:36:56 sogod [2020]: 192.168.X.Y "POST /SOGo/Microsoft-Server-ActiveSync?Cmd=Sync&User=markus@mrmarkuz.public.domain&DeviceId=A3BDF14BB4683219BA077A20535A0E002&DeviceType=WindowsOutlook15 HTTP/1.1" 200 0/897 1.459 - - 0

What does a ping to your alias return?

Thank you very much Mr. Neuberger for the help!

Wünsche noch einen schönen Abend :grinning: :grinning:

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