Audio randomly not working, calling again works fine.

[Darkneopulse]

Hi all,
Strange issue I'm having with a client at the moment, they have 2 sites connected to the same FQDN, all connected with STUN. 1 site is having no(reported) issues, the second site is randomly having issues where occasionally the caller can't hear the client or the client can't hear the caller but when either party calls again the line works perfectly. If more information is required please let me know, I'm not really sure where to start troubleshooting this issue so any help is greatly appreciated.

 

[Allen_Miller]

Site 2 is set up according to standards - static IP's for phones; unique ports for SIP & RTP for all phones and appropriate port forwarding rules at remote router?
If you need more help I would open ticket with support info plus a capture illustrating the problem.

 

[Darkneopulse]

Unfortunately I didn't set these up to begin with so I believe they are on DHCP and currently have identical ports for SIP and RTP which I'm going to change now. Port Forwarding rules appear to be set correctly, same modem and configuration as site 1.
Thanks for your reply Allen, much appreciated.

 

[Allen_Miller]

I would say that if you had DHCP for the phones then probably the remote site port forwarding rules are not correct?
If you use SBC instead of STUN then local extension-extension calls will not go out over WAN and back and will just stay local. If you change from STUN to SBC you will have to open ticket with 3CX to remove your MACs from RPS or else wait 2 weeks or something like that for phones to be released from RPS.
Good luck.