Although Office Communications Server 2007 R2 supports virtualization for some server roles and features, virtualization of XMPP Gateway is not supported.

Collocation of XMPP Gateway with any other server role is not supported. And i guess that is because  XMPP listens on the following ports, (which may also require firewall configuration):

5061: SIP connection

5269: XMPP connection

However the gateway is licensed as Additional Software to OCS 2007 R2, meaning that there is no additional license cost associated with deploying the gateway for OCS 2007 R2 licenses.

You need to add a new DNS SRV record looking like this,

And then configure the edge server by adding the XMPP Gateway as if it were another federated partner.

Then there is some additional configuration regarding certificates and stuff to be done in the XMPP GW, you can read more about the additional steps in the documentation available here.

After you deploy the XMPP Gateway, Office Communications Server users and XMPP users can do the following:

· Add and Delete each other as contacts.

· Publish presence and subscribe for each other presence.

· Engage in one-to-one conversations.