This is just a brief summary of my (FRUSTRATING) experience – perhaps it might help someone else.
I tried to move from a locally hosted Trixbox with about 15 SNOM phones behind a pfsense firewall (2.1) to a FreePBX (2.10.1.9 Distro) hosted at Vitelity Communications.
I was having significant registration problems with several phones, especially the SNOM 300 models. The problems were intermittent. The phones would register, then go unregistered. Some phone were completely reliable. Others would not register at all.
The most common error on the SNOM logs was:
16/8/2013 12:33:42 [CRITIC] PHN: SIP: packet 1000035 dest invalid udp:###.###.###.###:5060 for Request DISCOVER/-
16/8/2013 12:34:14 [ERROR ] PHN: SIP: transaction_timeout udp: 1000034 (32000)
16/8/2013 12:34:14 [ERROR ] PHN: SIP: transport error: 1000034 -> udp:###.###.###.###:5060
16/8/2013 12:34:14 [NOTICE] PHN: SIP: Add dirty host: udp:###.###.###.###:5060 (0 sec)
16/8/2013 12:34:14 [NOTICE] PHN: SIP: final transport error: 1000034 -> udp:###.###.###.###:5060
16/8/2013 12:34:14 [ERROR ] PHN: SIP: transport error 1000034: generating fake 599
16/8/2013 12:34:14 [ERROR ] PHN: SIP: Registrar timed out
16/8/2013 12:35:16 [NOTICE] PHN: TPL: Socket 25 idle/connect timeout
These are some of the things I tried based on suggestions from SNOM, Vitelity, the FreePBX forum, pfsense, and more:
RESET all snom phones to factory default
SNOM Identities: Change RTP Encryption to OFF on the RTP tab.
Set all registrars in SNOM identities to IP’s rather than URL’s (avoiding DNS Lookup)
Firewall NAT setting incoming rules for port 5060-5061 and 10000-20000 to 192.168.1.0 (broadcast?)
Firewall Rules: Open all ports to the remote vitelity server.
A very knowledgeable poster on the FreePBX forums said it was a NAT error and that I should set up a VPN with Vitelity. This was not feasible.
Eventually, I gave up and installed a FreePBX Distro locally. I would have liked to get the hosted solution working but nobody seemed to have the necessary knowledge of the vitelity system, SNOM phones, and the pfsense firewall. Everyone said it was someone else’s fault. Maybe once I’m running smoothly I’ll try the hosted system again. Then again, maybe not.
The change in RTP was, though, required on every SNOM phone.