Comcast change IP address [closed]

It won't help. You are banned. Changing your IP address won't change you. You will still be banned.

You do not have a technical problem.

My question is: can I purchase a modem and [attach] it to the gateway to change my IP address?

Addresses are handed out by Comcast. There is no real way around this. What your betting on is that you can "trick" Comcast into an IP change via new hardware, which is a potentially expensive proposition with a (charitable) 50/50 chance it might work.

People often complain that their dynamic IPs change too often but with Comcast as my ISP, I can say my experience is different — I haven't had my "dynamic" IP change for almost 2 years through 3 hardware changes... so yeah. Hardware changes FTW! ;-)