Sometimes when trying to browse forums or websites even for the first time, there is this nasty error message displayed whichgoes something like this “Your IP has been blocked, if you think this is a mistake, please contact webmaster@website.com”
This happens when ISPs assign IP addresses to many clients and some abuse it through sending spam and so on. The new systems that get this IP address are banned on many sites due to this reason.
Here is a quick way to find if current IP address that you have been assigned is on any blacklist or not :
Go to blacklistalert.org and hit “Check” as it automatically detects your IP address. Any other IP address can also be checked.
Then a list is generated showing where the specific IP that you are using right now is blocked. For more info, click the “See why” link next to lists where IP is shown as blacklisted (red entries). This is more common when using large ISPs since they give out a lot of IPs, some of them are bound to be blacklisted somewhere.