In this post, we are going to use a possible workaround for Sophos Firewall (XG) users whom experience drops in VoIP calls when it is due to a deficient or below average connection quality. As long as it does not coincide with bad SIP configuration, VoIP problems generally occur due to UDP time-out value.
Sophos Firewall OS has a default UDP wait time of 60 seconds, which is generally low for reliable VoIP communication. Usually, the VoIP provider sets the recommended UDP time-out for stable communication, and the common or usual value is 150 seconds, which is perfect for most VoIP scenarios.
To verify the current UDP timeout value, type from the command line interface (CLI) by choosing option 4 “Device Console” the following command:
In order to change the UDP “time-out” value to 150 seconds, type the following:
Check that the new “time-out” value has changed from 60 seconds to 150 seconds.