How to find out what ports my ISP is blocking?

[Diablo2K]

How do I find out what ports my ISP is blocking? They have not responded to my E-Mails and I keep getting errors saying I am behind a firewall. I turned off the Windows SP-2 Firewall and I still get the Error. I am Running on a DSL connection. Is it possible to find what ports are being blocked? Also is it possible that theres a Firewall built into the DSL modem?
I hate my ISP but it is this crapy 256k DSL or Dialup and I really dont want to go back to Dial Up!

 

[jimnms]

Turn off any software firewall, and make sure you're not behind a hardware firewall. Go to grc.com and click the shields up page. After you do any of the port scans, it will give you detailed instructions on how to detect which ports are being blocked by your ISP.

 

[lomn75]

its entirely possible you have a firewall in your modem. Mine does, though I have it disabled in favor of the Linksys box sitting behind it.

 

[Diablo2K]

Here is a quote from my ISP

If you have DSL then yes, you are behind a DHCP firewall. If you need to bypass this free service, then you will have to go with a static IP address. The cost for this is $10.00 a month.

Hummmmm, a free service that I have to pay to get rid of, I dont really like that very much but I dont have alot of options. But I kinda like the idea of a Static IP address even tho I have no real use for one, It isn't like I can run any kind of server on a 256/128k DSL with really crappy ping rates. What do you all think I should do?

My ISP SUCKS!

 

[Diablo2K]

its entirely possible you have a firewall in your modem. Mine does, though I have it disabled in favor of the Linksys box sitting behind it.

How would I check if theres a firewall in the modem? And if I do how would I disable it?

 

[lomn75]

manual? google the model number of the modem?