I am in the process of migrating users from OCS to Lync via a backcompat configuration. I've seen that the onboard OCS firewall is blocking port 1742, from all the servers in the Lync Front End pool. This is blocking me from migrating users from OCS to Lync, with Dcom errors on the Lync FE. Has anyone seen this before? I have no record of Lync using anything other than port 135 for the dcom process.