[VoiceOps] Ghost calls - Sipvicious?
David.Hiers at adp.com
Tue Nov 12 19:05:50 EST 2013
Maybe someone is spoofing your SBC IP address?
If the phone/UAS starts ringing as soon as it receives an INVITE from the UAC, then the user is presented with a ringing call that can never be answered. This unanswerable call might look quite a bit like an answered call with no audio.
I can't see what useful info would be gained from such spoofing, but enough of these could DOS you pretty hard.
From: VoiceOps [mailto:voiceops-bounces at voiceops.org] On Behalf Of Jay Hennigan
Sent: Tuesday, November 12, 2013 15:38
Subject: [VoiceOps] Ghost calls - Sipvicious?
We operate a hosted VoIP platform using Broadworks and over 90% Polycom phones. We have a number of customers at diverse locations recently reporting dead-air calls. These typically come from a source ANI of 100 or 7070 and have no audio.
Most of the phones are behind Adtran TA900 series IADs with NAT and a SIP access list allowing only our own SBCs.
The calls don't show up in our SBC logs, nor do they show in the MOS graphs on the Adtran voice quality monitoring.
Any ideas or suggestions on what is causing this or how to stop it?
Jay Hennigan - CCIE #7880 - Network Engineering - jay at impulse.net Impulse Internet Service - http://www.impulse.net/ Your local telephone and internet company - 805 884-6323 - WB6RDV _______________________________________________
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