Between my PC and the internet is a firewall which I have no access to. I think there may be more than one firewall. Is there a tool/application I can use to see what ports are blocked by a firewall?
How can I find out what ports are blocked by a firewall?
Archived thread 1000062 from Networking & Wireless. Markdown source: Networking_&_Wireless/thread_1000062_How_can_I_find_out_what_ports_are_blocked_by_a__fi.md
Try running [[COLOR="Red"]ShieldsUp[/COLOR]]("http://www.grc.com/") which is a good well-known online tool for checking ports.
typically speaking port 139 and 23 is usually blocked by your ISP, 25 is common now a days as well
a lot of times, your router blocks ports. log into your router and find out
If you have the ability to loop around the firewall, you can run a port scan on the external ip address using System-->Administration-->Network Tools-->Port Scan.
Edit: I'm not sure if the bug has been fixed yet, but you may get some false positives up in the higher port ranges.
Jim