On the Microsoft Front End server, use the New-CsStaticRoute and Set-CsStaticRoutingConfiguration cmdlets to create a static route. The static route will route signaling from the Microsoft Front End to the Domain 2 Presence Services federation relay component by specifying the trust application pool identifier, the internal domain (Domain 2) and port 5063.
Create a second static route that will route signaling from the Microsoft Front End to the Domain 2 Presence Services federation relay component by specifying the same trusted application pool identifier, the external domain (Domain 1) and port 5063. The Domain 2 Presence Services will forward the signaling to the Domain 1 Presence Services through Inter-PS federation. For more information, see Configuring Microsoft Front End server Trusted Application Pool, Trusted Application and Static Route.