Cookie to prevent access of unwanted user

[Mark Hewitt]

Thats exactly what I'm looking for. Any pointers on how to do this. Or places to look I can get examples of the code I need?

Also my site uses multiple sub-domains
e.g. site1.motorsportforum.com
site2.motorsportforum.com
I assume for the purposes of cookies these are treated as two seperate domains and a process running under the site2 domain would not be able to look at the site1 cookie?

I wonder if there is some way to make sure the checkipban function will always run from the same domain name. Explicitly call it from a program perhaps. So this person cannot just type in a new random subdomain.