EPM Config: Eliminating unwanted SIPVicious Calls to my Polycom IP450

I am using the End Point Manager in FreePBX to configure and manage my Polycom IP450 phones. I have about 10 and only one has a problem where they received 20+ SIP calls a day from fictitious sources. This particular phone is remote and sitting behind a Netgear WNDR4500 wireless router.

Through my research it looks like I need to add a config to the mac.cfg file for the Polycom phone in Endpoint Manager as follows: voIpProt.SIP.requestValidation voIpProt.SIP.requestValidation.1.method=“source” voIpProt.SIP.requestValidation.1.request=“INVITE”

This apparently would reject requests that come from any other server than the registered FreePBX / Asterisk server. Is that correct?

When I attempt to add this setting to the basefile for the IP450 in EPM I am not sure how to do it so that it gets pushed via tftp to all handsets. I am not sure what I need to put in the File, Section, Parameter and Value sections of the popup box in EPM. Am I in the right place?

Any help or direction would be greatly appreciated to help end these non stop annoyances. Also I assume it is not through our server because we have dissallowed anonymous calls. Also nothing in the server log show the activity that is showing on the end users phone.

Thank you!