So, I recently got banned from DoTA cash and made it a personal mission to ban evade them. They use I.P bans, so changing your account name/cd keys won't help. Depending on your Internet provider, your I.P "lease time" is anywhere from 3 days to many months, this is the amount of time you'll have that same I.P.
Now, if you have Comcast like I do, the lease time is very long and traditional methods for getting a new I.P just don't work. There's only one way I've found to reliably change your I.P on demand:
For this to work, you must be using a router. If you're plugged directly into a modem, you're fucked.
Step 1) Access your router. Open firefox or Internet explorer and type in the routers address, usually 192.168.0.1 - if you're not sure, look on the back of the router, it will list it. Log into the router, if you haven't ever set it up, the default is usually "admin" with no password. Again, these are listed on the back of the router.
Step 2) Depending on the router you use, the location might be a little different but the goal is the same: Find the "manual configuration" option, and look for where it lists the "MAC Address". This should be a 12 digit number, in sets of 2's. This number is a unique hardware identifier specific to your router, when your Modem is connected to it your Internet Service Provider will assign you an I.P based off of your Router's MAC address. What you'll want to do is, modify this number in one or two spots. Change a C to a D, or a F to a G somewhere along there, what you change isn't terribly important.
Step 3) Save settings.
Step 4) Unplug your MODEM for 2-3 minutes, then plug it back in.
Viola, new I.P address.