Wednesday, December 24, 2014

Ubiquiti EdgeMax blocking SIP video calls

I struggled for a while trying to figure out why a SIP video client (Polycom Video) on an iPad would register with our SIP gateway at the corporate office but was unable to make calls.  Disconnecting the iPad from the Wifi and using Cellular data the device would register and make calls just fine, but who wants to pay the cell bill for regular video calls.  We had this problem with three different people and we found the common item with each was an Ubiquiti EdgeMax firewall (in our case running v1.5 and 1.6 code base)

After digging a bit I found that the EdgeMax router has a SIP "helper" service (or SIP ALG Application-level gateway) that was causing the issue.  Executing the following commands at the CLI solved the issue.

set system conntrack modules sip disable

As a reference I also found the following articles in the Ubiquiti forums

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