Operators who use different Servers and Realms for Registrar and Calls

Some VoIP operators (eg. Blueface) use a server for account registrations and a different server for making calls, but they also use different REALMs. Although this solution is not prohibited by the standard, it is rarely used.

The phenomenon therefore appears in these terms:

  • in the PBX the VoIP account is typically configured with the credentials (proxy, Realm, user and password) provided by the operator for account registration
  • Using the default Realm to register the account, it registers correctly and you can make outgoing but not incoming calls.
  • Conversely, using the second Realm (often not communicated by the operator), you can receive incoming calls, but not make outgoing calls, because the account is no longer registered.


  • create gateway in PBX 2, one to be used for registration and incoming calls, the other to make outgoing calls
  • use the respective Realms on each account (having all the account details communicated by the operator)
  • leave the registration on the account that will be used for incoming calls active
  • for the other account, activate registration ONLY when creating the gateway to set the respective credentials (different from the first, especially with regard to proxy, username and realm), save the gateway configuration but then modify it and disable registration.