Polycom spam calls or unknown SIP calls
1) Whitelist of IP's on the codec. This would remove all inbound traffic to
your codecs except what is programmed into the codec. However you would have to
have all IP devices that can connect to the codecs, each codec, your iPads and
anyone else who is supposed to be able to call in, set to a static IP address
and then program them into the codec. Or at least if you know the inbound IP
you can add it to the whitelist.
2) Polycom sells something called a Firewall Traversal Solution or a R-Pad
SBC (session broadcast control). These are device(s?) that are purchased and
added to the network environment. Their sole purpose is to handle all port
traffic for the video conferencing systems. I do not know the cost or the scope
of installing these but it is another option to resolve this issue.