Minecraft Flood

Hi guys! these days i had few problems with my minecraft server... few kids tryed to stop my server by flooding.I don't know how to call this, i heared something about
"fake players" or "fake bots".
So the chat was like:
haha loged in
hgweh loged in
gwhqwhw loged in
hrwhhe loged in...
Where can i get something like this? and well can i protect my server from flooders?
Please reply


Thanks!

SorceOne

Spam bots (both are paid products):
1. PWN4G3
2. Worlds End

Protection:
AntiBot (its a bukkit plugin)