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Regular Visitor


Does anyone know what comcast term would be the same as SIP ALG or SIP Transformation

I'm trying to get them to shut it off, have no audio on calls.

Problem Solver


No Comcast does not use SIP. The question is why are you trying to shut off their digital phone service in the first place. If you are having issues of no audio when connecting to your Comcast Digital phone service. You need to first try a different phone connected to the eMTA. If still no audio. Then you need to file a trouble ticket with Comcast, regarding this problem.
Frequent Visitor


SIP ALG (Application Level Gateway) is often a defaulted on feature for routers like Netgear.  It rewrites the SDP for the media exchange of SIP Requests & Responses to the public IP & Port of of the NAT.


You didn't say what this was for.  If you're phone service is thru Comcast then there is nothing for you to do and SIP ALG does not apply.  If you're trying to get a SIP Softphone like X-lite to work then you only want to turn off SIP ALG on your router if the remote SIP Server you're connecting to supports Remote NAT Traversal.  If you're trying to do peer to peer SIP with another Softphone, so you and your peer are both behind NATs, then it requires STUN/TURN/ICE which is beyond the scope I can help you with and you'd need to talk to your SIP vendor/provider.


Assuming you're connecting to a SIP Server, you need to ask them if you should have SIP ALG on or off but in either case it is not a feature of the cable modems.  It is an optional and common feature of Routers.  I don't know if the combo modem/router devices support it or not but D-Link, Netgear and all the high end routers do.  Lookup the documentation for your specific router.

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