Hi, guys! Maybe someone can help me with such a problem:
My company has 3 offices and several shops. Our offices are united in a single vpn-network via mikrotik routers with the address 10.10.10.0/24. The first office has a Mikrotik router which is used as the l2tp-ipsec server, the gsm gate and a server with a vm of FreePBX on it, there is no sip users in this office. Two other offices have networks 192.168.0.0/24 and 192.168.100.0/24 and are using sip. everything is going well, the calls are passing good as to the internal numbers/lines, so to the external. A couple of days ago we started to connect our shops to the vpn. 2 shops with the networks 192.168.200.0 and 300.0 /24 were connected, the traffic is passing through and the phones register in the freepbx, but when we try to make a call no matter from the shop or into it we have a single-side audibility: on the side of the shop they hear everything, but on the other no one can hear what 's said. And there is no matter whether it an internal or external call, always the same result: they hear me, i don’t hear them. The routes, the NAT and filter rules on client Mikrotiks are all the same, can anyone suggest where’s the problem or recommend where to dig?
Thanks
Post the config of the Mikrotik on the central site and on one of the shops, see my automatic signature for hints on how to anonymize it. Also, provide a diagram of the interconnection of the devices on the central site.
It is well possible that the RTP (audio) and SIP (signalling) are processed at different IP addresses at the central site, which is an arrangement which the SIP ALG (“helper”) on Mikrotik doesn’t handle well. The good news is that if all of your SIP devices can see each other via VPN with no NAT between the elements, you don’t need the SIP ALG to be active.