siili
Hello,
After rebooting a router with an openvpn client, the SIP phones failed to work on the LAN. On further investigation I found openvpn was passing ICMP (ping) and other traffic (TCP ports 80 and 443) but not UDP port 5060 (sip). The point of failure was identified with tcpdump. The traffic could be observed on both the LAN interface and tun0 for ICMP but only the LAN interface for UDP port 5060 indicating the traffic was not passing to the tunnel. This caused most but not all the phones to fail for some reason. After a reboot of the same router (Debian based) most phones started working. Oddly, one phone in particular did not work until I changed the IP address of the phone. I have seen this before. Any idea what might be causing this and what could be done to prevent it in the future?
Regards,
David Koski
