There are 2 issues here.
1. You only need to use the extip feature on the Tenor when the Tenor is on a private IP and the public IP side is dynamic. If the Tenor is connected directly to the public IP (even though it is dynamic), you do not need to use extip.
2. If you do need to use extip because Tenor is on a private IP, with dynamic public, then the gatekeeper MUST be a Quintum gatekeeper or Quintum product with gatekeeper built in.