Dynamic IPs bypass ban

Hello, I am having an annoying issue with someone on my forums who keep bypassing IP Bans because of his Dynamic IP. Everyday he creates a new account and annoy everyone the problem is that everyday I must go and ban the IP. Everyday it's the same thing. And his dynamic IP isn't something like xxx.xxx.xxx.1 xxx.xxx.xxx.2

His IPs are always different ex:

67.80.20.25
67.55.104.203
68.52.12.238
etc...

There is no way i can think of to ban his IP without him bypassing it everyday. (Also he has 2 different ISP) (One from his mother's and one from his father's) So is there a way I can do so he can't come back everytime? Also both of his parents use Comcast is there a way to block "comcast" ISP? Any help will make me happy!

Set it up where administrators have to approve new members.

I just did this and I tried to create myself a "test" account where am I supposed to receive the note that a user is registering? I checked my Inbox and it didn't show there.

Try your email.

also ban the Email address as the member will get sick of making new Email addresses each time he she wants to log in

Seems that he has a lot of patience APE. I've been banning his IP/Email/Username for about a week. I notcied that the email was sent to my old email address I changed it to my new Email it's alright now Thanks