Spotted this article referenced in a thread on DSLReports.com, and even though it’s from four years ago we thought it might be worth mentioning:

There are a number of tutorials for people trying to setup blacklisting for their Asterisk server, but they all seem to assume that there is only one user on the server, or at least all users want to share the same blacklist.

Since I host for multiple, unrelated people, they don’t necessarily want to share the same blacklist, so I had to come up with a configuration that would work for all customers.

Here are the changes I made (for Asterisk 1.4)

This may or may not need to be tweaked a bit to work with newer versions of Asterisk. Unfortunately, the thread on DSLReports leaves the impression that it might take a bit of work to integrate it into FreePBX, so you are on your own if you want to attempt that.

Full article here:
Asterisk: Blacklisting For Multiple Users (Lime Daley)
Related Link:
How to hack the FreePBX blacklist for better call blocking capability