Ports Blocked by ISP

[trickster]

Is there any easy way of knowing what ports are being blocked by my ISP, without calling them up and asking?

[The_Whizzard]

By doing a portscan from an outside source(dlsreports.com, etc.) you should be able to tell which ports are blocked. They should come up as "Stealth". You might also be able to use nessus from your linux box to scan the netblock your IP is on.

[Compunuts]

Or you could nmap yourself with your IP.