More of what I was thinking was a killfile controlled by the user, uploaded to the server when updated, that would allow the server to filter messages. You cou

More of what I was thinking was a killfile controlled by the user, uploaded to the server when updated, that would allow the server to filter messages. You could allow shared blocked lists and support wildcards with whitelist exceptions. In this way, you can block everyone and whitelist who you want, so changing your IRC user name does not help. In most cases, unless the person connects from somewhere else, specifying a sufficiently wildcarded netmask for the host part also prevents the IRC nick change.