IP Phone - VPN
A new client called talking about a phone issue that they had been experiencing. The client has multiple locations with an IP Phone system at their main location. The other two locations have IP phones and receive calls via a VPN (Virtual Private Network) tunnel from the head end. Every day at noon calls that are placed to the remote site would go through however voice traffic was only working to the remote site. Meaning, the employee would hear the person who placed the call but their voice would not be heard to the caller.
This was an interesting problem to address. First, the VPN tunnel is up and functioning correctly since the voice traffic can reach the branch office. Second, the problem re-occurs every day at noon exactly until the router is rebooted.
We started asking questions and learned that a new computer was put in up front at the main location and this computer is only used by staff in the afternoon each day. Yes, the computer is turned on each day at...you guessed it - noon.
We logged onto the computer and ran the usual virus scans, network tests, etc... everything came out fine. Then we checked the IP address of it on the network and found out that the computer had been assigned the same internal IP as the IP Phone system. When the computer was booted up it would broadcast its IP address to the network. The remote IP phones just have one purpose, to call home via IP address. They can receive calls no problem but when people speak back their packets are delivered back across the VPN to...yes, the upfront computer. A quick IP change on the new computer, a router reboot to clear the cache and all voice communication has been working as designed!