URL Redirect

I’m new so don’t throw stones. I need to know if you use scripts to redirect to a URL.
This is my situation. I have a list of IP’s NOT currently in use by DHCP. If someone plugs another computer, say a home computer, into our LAN and gets an IP from DHCP I want them redirected to a HTML pages that tells them to get off.
If it’s a firewall rule I don’t know how to make it redirect. All I can do now is have it do an ICMP reject which does work but it doesn’t get my point accross to them.
Thanks

Have a look at this thread:

http://forum.mikrotik.com//viewtopic.php?t=9377

There are others as well, mostly people want to redirect non-paying customers.