Identify accounts with duplicate IPs

[Keith10247]

So in line with all the recent spam discussions. I have a question for you all.

I have noticed that we have certain spammers signing up for accounts using a range of IP addresses. I am looking for a way to find these users easily without having to go use the admincp.

I ran the command:

select username, ipaddress, COUNT(*) as n from user Group by ipaddress having n > 4;

It came back with some results but only shows me registering IPs for the users. I have instances where the users will register from 1 IP address and post from another.

How does one query the database to show duplicate IPs from not only the registration but from the other IPs that are used?

Thanks in advanced!

Regards,
Keith