Using VOIP.MS service I had no problems for months with a single device. Recently I added a second device (an Obi202) and set it up properly (e.g. using its own sub-account at voip.ms).
Started having problems with one device (or the other) failing to register, and it seemed periodic.
I checked the Peplink / Status / Active Sessions and both devices were showing up as expected.
Per advice of VOIP.MS I moved the second device from 5060 to 5080 and it seems more stable now. I did not turn off the Peplink SIP ALG, but did add port 5080 under Peplink/Network/Misc/Service Passthrough/SIP/Define Custom signal port.
My question: do I really need to have the two devices connecting on different ports? One would expect that the Peplink built in ALG should handle this, no?
Edit to add:
At one point when device 1 wasn’t registered, I looked at my voip.ms account status and it showed that device 2 wasn’t registered, which was backwards from reality. This makes me wonder if the Peplink may have been routing packets meant for device 1 to device 2 or vice-versa.
Edit 2 to add:
Both devices are on the same VLAN, in case that’s relevant.
It sounds like f you have multiple SIP devices on port 5060, then the Peplink will do NAT/port translation, and it may choose port 1025 (which many ISPs block) resulting in problems. I’m not clear if this is an ISP problem or a Peplink issue that could be fixed?
In any case, by hard-coding one of my SIP devices to use port 5080 instead of 5060, I’ve had zero problems for over a week.