[Technical] “Wiretapping” with VOIP

We do have an appointment with a lactation specialist on Monday, and I spent a good chunk of Friday calling between the doctor’s office and the insurance company to see if they’ll be covering part of the cost. We likely won’t find out before we go, however. But, the experience inspired me to do something I’d been thinking of doing for a while for situations such as these: hooking my computer up to record phone calls to companies.

My first thought was to dig up a modem from around the house and try to hook that up in such a way that the computer could record via it. But then my second thought was that since our phone service is VoIP (Vonage), it ought to be possible to just collect the digital data that’s already there and record calls that way.

Here’s what I did. I set up our switch (A small-business-grade PowerConnect 2716) to have two of its ports on a separate VLAN, so that they were disconnected from my “normal” internal network, and only connected to each other. Then, rather than the cable modem being plugged directly into the Vonage router (which serves as my home network router), it gets plugged into this separate two-port virtual switch, and the other port gets plugged into the Vonage router. Then, I set up port mirroring, so that all the traffic that goes to and from the router gets copied to another port. That port gets plugged into the spare network card on my computer. (That is, my computer has its normal network card for day-to-day use, and a separate network card that doesn’t even have an IP, it’s just there to listen to a copy of the traffic happening between the cable modem and the Vonage router.)

Now I have a method of sniffing my Internet network traffic. This may turn out to be even more useful when the kids grow up some and I want to add more Internet monitoring. But for right now, I just want something that captures the SIP packets that Vonage uses and assembles them into audio files for me. I discovered Oreka, which seems to do the job quite nicely. I just need to have the Oreka service running whenever I want to record a call, and it automatically puts the spare network card into sniffing mode and writes out WAV files for all calls that happen while it’s running.

All in all, it was much easier and works much better than I thought it would at first. I’ve looked up the wiretapping laws, and Google’s results say that Massachusetts is an “all-party consent” state, so I need to make sure to notify the other party when I’m recording a call. But I think my wife is actually looking forward to saying “This call is being recorded for quality assurance purposes.”