random player joining/leaving

i have a random player called MCI, who wont stop just joining and leaving the server, it annoyed me so much that i just banned him but he still trys to join, even if he is banned, if you type the ip of the user in your browser the ip 198.27.83.157 will link to http://www.minecraft-index.com/ a voting site.

This doesn't really concern me but i'm just wondering if maybe its a bot or something?