I had a call today from somebody who was trying to use an Avaya IP Phone from their office at home. The phone has built-in IPSec VPN capability, and their phone switch is some distance away on – surprisingly – a DSL line. Call quality is not an issue, which is testament to Zen Internet‘s network quality.
In the office, the phone works fine. At home, it fails to establish a VPN, displaying an “Invalid PSK” error. Looking on the VPN router at the site with the softswitch, I see nothing untoward, so I set about asking the caller to tell me his default gateway address – which is the same address as the network range that the softswitch is no. No prizes for guessing why it doesn’t work.
Here I was, expecting a full-on IPSec debugging session, and it turns out to be IP addresses.