Hi,

We have a Mikrotik hEX RB750Gr3 5-port Ethernet Gigabit Router, with RouterOS 6.48.2.

We're located in Canada.

We had a new Panasonic VoIP PBX (NS700) in house installed by a firm that does just that, 6 months ago.
All the port forwarding were set in the Mikrotik router according to their specifications.
Since then we have the following trouble:
It's always the same person who answer the calls of the business. 2 to 5 times a day, when she answers, she cannot hear the customer and the customer cannot hear her. She hangs up, the customer calls back and it always work the second time. Usually no one has trouble doing outgoing calls.

Any Ideas how we could locate the problem with this?

Download a SIP ALG port tester and run it on a PC on your network to test the router. You want SIP ALG False/Disabled for UDP.

Hi C5Z,

Yeah the SIP ALG is turned off in the router. I also had used a tester on a PC to confirm it.

Since many week the phone is working great. The person answering the phone said it was almost flawless. Just sometimes, when she answers, the other person already hung up. But that could be just that.

I don't know if it helped, but I had change a few rules in the firewall. I had like 12 rules or so to block Inter-LANs traffic. It could be summarized to 1 rule that did the same job. So one rule to replace 12.
Also I had added QoS, prioritizing the phone traffic.

It might all have played in our favor.

Thanks!