Hi all,

In the process of setting up a new Lync server for using with a SIP trunk to start getting rid of our old school PBX.

Our SIP provider requires that the source of the data packets we send them comes from one of our public IP addresses instead of from and internal address that then goes through NAT through our firewall. To this end I have setup a DMZ with the network in the following config-

Internet Router <---> Network Switch <---> DMZ VLAN <---> Core Switch <---> Public facing NIC on Lync Server

With the default gateway of our Internet Router set on the Public facing NIC of the Lync Server I can see comms flowing freely between by server and the SIP endpoint (so all works ok here).

Naturaly you can't have two default gateways so I have removed the default gateway from the private facing NIC on the Lync server.

To get our clients to still be able to talk to the Lync server I have tried to setup routing as per this guide here - Windows 2008 / Multi-subnet clusters and using static routes. - Tim McMichael - Site Home - TechNet Blogs

I've tried both the route add and netsh methods but arn't getting anywhere fast (whenever I do a tracert to a internal IP address it always tries to go out the public facing default gateway instead of along the route I have defined).

So.........any clues on what to try next?