To block prefixes

[levter]

Is it possible to block prefixes on the gw?

I am interesting in blocking prefixes in two direction:

calls coming from PSTN into VoIP network and from VoIP into PSTN.

Is it possible?

[t-baumann]

Yes. To block the calls coming from the PSTN side you can use the num-exp command. Say you wanted to block all calls going to 1408....... then you can add the following command

num-exp 1408....... 9408.......

If you don't have a VoIP dial-peer that only excepts 1+ or 011+ then it kills the call with a No Route to Destination.

If you us a gatekeeper for routing then blocking on the VoIP side is easy by putting a zone prefix gw-priority 0 in teh gatekeeper this will block VoIP patterns with the same message of No Route to Destination.