The invention generally concerns the issue of providing connectivity between two different address realms, generally referred to as an inside realm and an outside realm, by establishing connections through an intermediate gateway. The gateway normally has a number of outside-realm gateway addresses for enabling representation of inside-realm nodes in the outside realm. In a first aspect, support for flexible outside-realm initiated connections is enabled by dynamically establishing new gateway connection states triggered, for each new connection, by a respective user-resource identifier query initiated from a corresponding outside node. In a second aspect of the invention, intelligent use of predetermined connection information in the process of setting up new gateway connection states makes it possible to significantly increase the number of connections that can be simultaneously supported by the gateway using a limited number of outside-realm addresses.