We have a client that we just moved their system offsite into the cloud (well, really our cloud) and they were having CONSTANT phones dropping off - PJSIP mostly remedied that (they stopped becoming unreachable) but when you would call in and hit a ring group, some of the phones in the ring group would not ring - it was driving me crazy - we tried adjusting things like qualifyfrequency, played with the firewalls, and even switched out some phones (they had some REALLY old Polycom’s) and nothing helped - just switched them to TCP and the problem has COMPLETELY disappeared! I am surprised to say the least - has anyone else seen this? Had bad experiences with using all TCP?
I think it’s a miracle, but probably only because I have been fighting this for days.
Anybody have any horror stories about using TCP instead of UDP?
Generally, when running FreePBX behind a “conflictive” NAT device, the keepalive parameter can help keeping the connection open so the firewall won’t close the session prematurely.
That is true - keepalive was enabled all along through all the permutations we tried - that did not fix the problem. Switching to TCP fixed it when everything else would not.
There is another current thread here that might pertain, I contend that udp can allow spoofed connections from perhaps a 400 pound guy in New Zealand, It is likely that restricting yourself to tcp where possible
Just a challenge to those that have a better understanding . . . .
Bandwidth is good (100MbitD/20MbitU) at the customer site and really good (1GbitU/D) at my CoLo - I am just trying to find out if anybody has had any real world problems because it seems to work perfectly.
Couple of things I noticed while troubleshooting:
I had knocked the Qualify time down to 20sec - this seemed to be necessary to get 95% of the phones to have a stable connection - it was in the end only 3 phones that I could never get stable - switching to TCP fixed that and in fact I switched back to a 60sec qualify and they were all still solid.
Voice Quality seems to have improved - without prompting, I got two comments that they sounded better - I wasn’t even asking.
The customer connection is Comcast, and they are terrible here as far as reliability and consistency goes - so maybe it was necessary in this case because of the circuit, but whatever - this is going to be my go-to solution in the future when this is a problem.