[Serusers] RTP Wiretapping

[Andres]

Java Rockx wrote:

>Hi All.
>
>I'm located in the US and would like to comply with the Communications
>Assistance for Law Enforcement Act (CALEA) that Congress passed which
>basically says that VoIP providers should have the ability to wiretap
>conversations for the FBI upon request.
>
>I use mediaproxy for NAT traversal. So my question is how can I be
>CALEA compliant? I assume I should be able to modify mediaproxy to
>write RTP streams to disk, but I'm unclear on how to "mix" both sides
>of the conversation.
>
>Can anyone help with a suggestion?
>
>  
>
Here is one suggestion.
Write a simple perl script that does the following:
1.  For example if they call you up and tell you to monitor user 5050111
2.  Your script will lookup him up in the location table and extract the 
IP ADDRESS
3.  Then your script will use tcpdump to collect all incoming/outgoing 
traffic from that IP.
4.  Then you import that capture into Ethereal and will be able to 
nicely decode the media stream (if its G711) into a playable file for 
any audio program (like Windows Media Player).
5.  If you are using other codecs then simply export the RTP stream into 
a file and then use other software to decode it. (if its G729 for 
example, you can download the decoder from Voiceage).

If you want something more elaborate, you can simply route the 
"monitored" subs via an Asterisk server which can save and decode all 
audio streams into simple WAV files.

Andres.



>Regards,
>Paul
>
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