No media connectivity with Lync Server 2010 collocated mediation server and external users

At a customer site there was a Lync Server 2010 that had been running for about a year. This solution was now going to be expanded with a collocated mediation server over a dedicated PSTN network card. The mediation server deployed fine and I added routes and tested connection with the SIP trunk provider over telnet, TCP 5060 and it seemed fine. Continue reading