This article explains how to use a DNS query to check if and how an Open Federation Service is set up to a domain.

To check the availability of a federation service on the internet, the command line tool nslookup is used.

To do this, open the Windows command prompts via key combination [Win]+[R], enter cmd and [Enter], and proceed as follows:

Verification of a SIP federation

in the Windows command prompt using the example of estos.de

c:>nslookup
>set type=ANY
>_sipfederationtls._tcp.estos.de
>quit

Verification of an XMPP federation 

in the Windows command prompt using the example of estos.de

c:>nslookup
>set type=ANY
>_xmpp-server._tcp.estos.de
>quit 

As a result, you will get the server name and port of the domain's federation service, which you can use to check a possible connection to the federation service with other tools, e.g. Telnet. Please note that this test only checks the technical requirements for the federation.

Federation is based on positions of trust. If the federation service cannot be used despite a technical connection, it should be checked whether additional configurations on the part of the federation partner might be required (e.g. approval of your own domain as a federation partner) and requested accordingly.