the only ways "what i know about" is to ether put the channel keyed.. /mode #channel +k som_key this means that you have to type /join #channel som_key to be able to join it.. or set in +i "invite only", this means that somone have to invite the person that wants to join this channel.. and the one doing the invite must be oped in that channel.. then you have another sulution for it.. it is to have a eggdrop bot running a TCL, this TCL makes every one joining the channel auth with a password, if the user dont give the pass to the bot the bot will kick that person.. "can also be set to ban", if you know what a eggdrop is and running one, then i can send you the TCL..
