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VoIP crackdown

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  • #28509

    hi. Im new to the VoIP world and have a question.
    I understand that in some countries VoIP is illegal, now how are the illegal operators detected or how do they avoid to be traced?



    To chase them: Look for places with phone lines and internet service. Very easy. Look for many calls only outgoing on phone lines.
    Listen to the calls (remember, on those places the phone company still operated by goverment agencies)

    To avoid them: Get the internet service on one building, send them via radio to another .

    Use GSM gateways, where the phone calls are sent out via cellular network.

    Use gateways that have many GSM SIMS cards per channel. The machine uses diferent SIM cards on every call, making very dificult to trace the calls. Looks like 300 cell phones making calls on diferent cities, but is only few gateways that get the sims changed every few hours.

    Pray like hell that they do not catch you. Some places are outright nasty if you get caught.
    Minimun they confiscate the equipment and whatever else they could get.


    Wouldnt be possible to use some kind of proxy so the gateway is obscured?


    If you control of both ends, the best way to trow them of the track is to make a VPN tunnel end to end.
    Not only the information is encripted now, but you get the extra benefit of a internal I.P. that is not on the net.
    All what the NET see is a lot of encripted pakages going back and forth.

    VOIP Control

    Lets go step by step, when you do VOIP the first thing you need is to asure the two way path for your voice traffic, even if you are behind NAT, second you need to make sure that you have enough bandwidth to complete calls with the amount of ports that you installed, if you are a wholesaler you may have 2 or 3 E1’s in the same location, this will require 1.5 to 2 Mbps of bandwidth and the behavior of that bandwidth is pretty much simetrical, Internet Service Providers that want to identify traffic will close some ports used by your gateway for billing and for gatekeeper authentication first like ports 1718, 1719 and 1720, then ports used by Radius AAA 1812 and 1813 and finally a little bit of monitoring of bandwith usage on the interfaces assigned to the customers using SNMP so you can verify the type of behavior of the customer’s traffic.
    Doing so you take down probably a big group of ilegal VOIP carriers.

Viewing 5 posts - 1 through 5 (of 5 total)
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