VoIP call issues over site-to-site VPN or with IPS configured
Resolve issues with VoIP call quality if you've configured a site-to-site VPN or IPS on Sophos Firewall.
If you've configured site-to-site VPN, IPS, or both on your Sophos Firewall, do as follows to resolve issues, such as VoIP call drops or poor quality calls:
set ips sip_preproc disable
This command turns off the preloaded IPS patterns for SIP.
set vpn conn-remove-tunnel-up disable
When IPS patterns are turned off, Sophos Firewall does not flush the connections when IPsec tunnels come up.