Technical TIP: SIP trunk showing unmonitored status due keep-alive timeout

Description

This article describes a scenario where the SIP trunk shows status unmonitored because SIP option messages did not receive an answer.

Scope

FortiVoice v7.2.x.

Solution

The SIP trunk shows an unmonitored status.

The SIP trunk profile is enabled with keep-alive (qualify-check-status) enabled.

config profile sip-setting
 edit SIPPROFILE
  set profile-type trunk
  set qualify-check-status enable<--
  set qualify-check-interval 60<--
 next
end

config trunk sip-peer
 edit TRUNK
  set sip-server 10.232.191.1
  set registration disable
  set sip-setting SIPPROFILE<--
 next
end

In packet capture, FortiVoice Admin can observe only unidirectional traffic.

Recommendations:

1. Review SIP traffic is allowed through all devices in the path to the SIP peer.

2. This is likely due to the strict policies on SIP peer that require the from-domain to match that of the FortiVoice server.

To fix this, explicitly set the Realm/Domain to the FortiVoice IP address or VIP address in case of HA.

In this case, the FortiVoice IP address is 172.20.72.14.

Example of configuration:

config trunk sip-peer
 edit TRUNK
  set realm 172.20.72.14
 next
end