The administration ID is used to identify the administration. This ID can look as follows: 2F1E4FC0-81FD-11DA-9156-00036A0F876A.
Retrieve ID via web service
The administration ID can be retrieved via the web service AdministrationID(sessionID, administrationName) method.
Search for ID in web interface
The administration ID can also be found by opening your administration in your domain and then right-click Contact info and open the link in a new tab.
You can then select the ID from the URL in the address bar.