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UDP time-out value causes VoIP calls to drop or have poor quality

What to do if VoIP calls drop or have poor quality.

Condition

VoIP calls drop or have poor quality.

Cause

If there are no errors in the SIP configuration, VoIP issues are usually due to the UDP time-out value.

Sophos Firewall has a default UDP time-out of 60 seconds which is usually low for reliable VoIP communication. Usually, your VoIP provider recommends a UDP time-out value, typically 150 seconds.

To change the current UDP time-out value from the command line interface (CLI), choose option 4. Device Console and do as follows:

Remedy

  1. Type: show advanced-firewall

    The output shows the current UDP time-out value next to UDP timeout stream.

  2. Type: set advanced-firewall udp-timeout-stream 150

    This command increases the UDP time-out to 150 seconds. If your provider recommends a different value, use that.