0

Ahoy friends. Currently i got 2 networks connected via routing. I got a VoIP device connected to one of the networks, to be routed to the other one. Everything else is working on this configuration of the network, only the phone is having trouble. Only i can hear persons speaking on the phone, but they can't hear me.

One, the remote network, having 192.168.1.0 subnet, the other, the home network 192.168.2.0. They are connected using a wireguard VPN connection, 10.0.0.1 and 10.0.0.2 interface which is running fine.

metwork

Traceroute as well as Ping works in both directions, so the routes are running fine. I got a Cisco SPA502G phone connected, and i want to make calls using my phone number in the home network. It works almost fine, but no one is able to hear me. Even though, according tcpdump -i wg0 udp port 5060 or udp portrange 7078-7110 -s 0 there is a traffic in both directions, RTP traffic. Also according to the Cisco Phone Web Interface there is a bi-directional traffic. Here some part of the log

21:56:13.398558 IP 10.0.0.1.7094 > 192.168.1.184.7092: UDP, length 112
21:56:13.416811 IP 192.168.1.184.7092 > fritz.box.7094: UDP, length 162
21:56:13.418592 IP 10.0.0.1.7094 > 192.168.1.184.7092: UDP, length 112
21:56:13.438534 IP 10.0.0.1.7094 > 192.168.1.184.7092: UDP, length 112
21:56:13.443806 IP 192.168.1.184.7092 > fritz.box.7094: UDP, length 162
21:56:13.458529 IP 10.0.0.1.7094 > 192.168.1.184.7092: UDP, length 112
21:56:13.469531 IP 192.168.1.184.7092 > fritz.box.7094: UDP, length 162
21:56:13.478549 IP 10.0.0.1.7094 > 192.168.1.184.7092: UDP, length 112
21:56:13.498550 IP 10.0.0.1.7094 > 192.168.1.184.7092: UDP, length 112

I got the following routes in both directions.

Remote network to target network:

ip route add 192.168.2.0/24 via 10.0.0.1

and ip route add 192.168.1.0/24 via 10.0.0.2

I thought it might be a common NAT issue or routing issue, but it's none of them So what can i try? Maybe another codec? Or something else?

EDIT: It seems to be a quite complicated NAT issue, but i don't know why. In my OpenWRT device, there is only a NAT related rule, for WAN zone --> Reject.

I have made a post on Cisco forums, and according to the SIP and RTP logs, only valid RTP logs are made into the direction to the phone.

The other ones may be invalid because of a NAT bug.

See here, the related post, unfortunately i didn't fully understand it.

https://community.cisco.com/t5/voice-systems/voip-phone-only-working-in-one-direction-vpn-routing/m-p/4046734/highlight/true#M55767

I got 2 Endpoints of the VPN, one is the OpenWRT device, and the other one, a network device in 192.168.2.0 network, which is connected to the router 192.168.2.57. Somehow it's currently not possible to get the traffic from this device. 192.168.2.57, or it's wg0 interface 10.0.0.2 to the router 192.168.2.1. Does someone knows how to do that?

Fabian Druschke
  • 1
  • 1
  • One-way voice is almost always a routing or firewall issue. But without seeing configurations, we'd just be guessing. Please edit your questions to include relevant device configurations. – Ron Trunk Mar 16 '20 at 14:14
  • Thanks, i tried to provide more information. I also got a link of the Cisco forums, the related issue to my problem, but even though i don't know much about networking stuff. https://community.cisco.com/t5/voice-systems/voip-phone-only-working-in-one-direction-vpn-routing/m-p/4046734/highlight/true#M55767 – Fabian Druschke Mar 16 '20 at 20:38

0 Answers0