I've had a lot of experience with VoIP over the years and during my time working at a large VoIP provider I saw a lot of fraud passing through all manner of PBX systems and hitting our network (asterisk, freepbx, 3cx, etc)...
Usually when we contacted the customer and let them know they had unusual calls attempting to terminate with us, they were very surprised. Although we blocked the calls most of the time, often a secondary/backup provider would then pass the calls through, costing them thousands in fraudulent calling.
So, for the last 12 months or so, i've been making a cloud based solution to help tackle the problem for people / companies. The idea is it sits between your PBX and the provider and watches for bad traffic. It doesn't actually take the calls though or need you to pass calls through it.
It's now time for me to suck it up and ask what people think and if they could give it a go on their test systems for me, which is why i'm here.
So, if anyone has some spare time and is happy to give me some constructive feedback i'd really appreciate it.
The website is: https://www.pbxshield.com
Let me know...