Use on 1:SNOTICE:*:

Comparing (if (*connect* iswm $1-) and then using $gettok($ident for nick,2,64) get the address...

For example:

*** Client connecting: moby_24 (ircap8@200-127-66-203.host.net) ()>----this is the message...

Code:
on ^1:SNOTICE:*:{
if (*Client connecting* iswm $1-) {
  if ($check($4 $remove($gettok($5,2,64),$chr(41)))) { <------------(alias for checking) 
     kline $remove($gettok($5,2,64),$chr(41)) rason...
}
}
}