We're having issues connecting with a vendor's Skype for Business installation. They have their own servers and are not using Microsoft's cloud Skype services. The problems are intermittent - it will work one time, but not the next. We've done a lot of logging and packet captures on the client end and haven't been able to find an issue. I've got all the recommended ports opened to the destination servers and have even tried with an any-any policy.
The vendor's 3rd party integrator that built their Skype system says that they've seen issues with packet inspection on firewalls and wanted to know if we could build a packet inspection exception on our firewall. I honestly have no idea how to do that, or if its even possible. Our firewall is an ASA 5520 running version 9.1(6)10 with all the default inspection configurations in place. Is there a way to do what they're asking?
Client connectivity may take two or three tries to connect - both voice and video show the same inconsistency. Once connected, desktop sharing may or may not work.