Inbound calls will just randomly stop working after 2-5 minutes

[robertj]

Hi All,

• After approx. 2-4minutes my inbound calls will just randomly stop working (no dial tone on inbound caller and no ringing on office phone)
  
  
• within those 2-4 minutes i can make inbound calls no problem (approx tried 13-18 times)
  
  
• Outbound still works without problem + internal extension calls (to handsets in different networks/WAN)

Here's the confusing/head scratching part

• when the inbound calls stop working, and i make a outbound call, the inbound calls return and then just randomly stop working again.
• 
  
• Restarting the SIP profile on the server will immediately fixes the inbound call issue. however then will stop working randomly again.

Environment:

• FusionPBX server (Debian 9 on Hyper-V) is behind a Dell SonicWall
• i don't have another on-prem environment to replicate the issue.

Has anyone else had similar issues, or what would be my first steps to take in troubleshooting where the issue might be?

 

[robertj]

Bump

 

[DigitalDaz]

Its very likely a NAT issue and just switching to TCP as the transport on your phones will probably fix it immediately.

By the sounds of it your NAT tunnels are timing out on the router. By restarting the sip profile etc, you are just refreshing those tunnels.

Many devices have very low timeouts for UDP, TCP tunnels are usually open much longer.

Enabling keepalives to keep the tunnels open would also fix this.

 

[robertj]

Hi all,
Solved the issue with DigitalDaz contribution/guidance wanted to share it with everyone

• in your Gateways Settings
• Advance settings
• Set Ping value (in sections)
  [Ping: If your server is behind NAT then the ping option can be used to keep the connection alive through the firewall. The ping interval is in seconds.]

Source: https://docs.fusionpbx.com/en/latest/accounts/gateways.html