Sometimes a well intentioned firewall can actually make SIP communication worse. The most common setting that adversly affects SIP calling is the "SIP ALG" feature. Under all circumstances it is a good idea to disable the SIP ALG feature of your firewall. Please see the images below as an example of where to find the SIP ALG in some common routers
Common Firewall Problems Print
Modified on: Mon, 8 May, 2017 at 11:58 AM
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