Block/Allow by IP in PAI


ACME SBC v9.1


I have returned to you guys to set a challenge.




We are getting some 'spoofed' calls coming in.

Presenting our numbers as the inbound caller number.

I know they are spoofed as:


1. we do not normally allow calls to go out and back in.


2.The spoofer has left PAI header which shows he is not using the same telco.



Now.
I can already block on inbound calls with the number in PAI using :


<user type="E164">44123456789</user>
<nexttype="void">!^.*$!sip:NotAllowed@0.0.0.0!</next>


In the lrt file and
next-hop

lrt:Block-PAI;key=$P-Asserted-Identity
in policy attributes.



What I am looking to do is expand on this and only allow calls in if they match our telcos IP.