I've run a small test server on a PC in our network for years. It is not getting much traffic and used to work fine with dyndns. Now it seems as incoming traffic to the lower ports are all blocked. Anyone know if 3BB started to block these ports, i.e. port 22, 80 and other low standard port? Yes I know I could use other ports but it's convenient to use standard ports and it has worked until now...

most likely

any software to check which ports are blocked?

any software to check which ports are blocked?

From your site, try this site:

https://www.grc.com/x/ne.dll?bh0bkyd2

You can just google "online port scanners" and get a long list of them. The ports appears to be blocked, I just wanted to know if anyone could confirm that 3BB now block incoming ports.

yes, 3BB block lower ports (80,443,3389,1723) if it find some traffic on your connection(e.g.WebCam).

Go virtual e.g. Live Mesh, it use ports 30000-40000.