I’m a software dev who’s wife owns a small business. She’s experiencing an issue where the Yealink Unicom phones stop getting service. At first it was the same phone not working consistently, with a second phone not working occasionally. We swapped the consistently broken phone with one from another desk and rebooted the entire network (modem, router, 2 switches, 2 patches) which seemed to work for a few minutes. But, the next morning 3 other phones are not getting service and the originally broken phones are working. The phone guys say it’s a network issue and we need to turn off “sip alg”. The network guy didn’t want to do that for security reasons. But he did turn off the sip alg and all of the phones lost service. The network guy has moved out of state isn’t very responsive. My network skills aren’t very strong and I don’t have access to any admin things. These phones have been installed and working for 2 – 3 years. There’s been no significant changes to the network that I’m aware of. all phones are hardwired and powered by that wire and provide internet to the employees computer. I’m trying to get on a call with the network guy and be his boots on the ground to help. I’m open to any suggestions on how to proceed.

Rebooting network – problem comes back
turning off sip alg – all phones stop working