This command will enable or disable part and quit messages from being viewed in rooms by local users.

/as security set reasons off

Part and quit messages add flavor to chat. But on the downside, they are very difficult to control. You can't effectively ban a user for an offensive quit message when they may not try to login again until the ban is gone. Most users will either use the default part/quit messages or use their parts and quits to put in a personal message that, much like an email .sig, says something about them. But a small number may use these messages in annoying ways. You can choose to allow the messages for the majority of legitimate users or remove them to prevent the abuse. They also can be annoying just for their length, even if they are interesting. If most of your rooms have a very large number of users, then the part/quit messages add to the scroll while not contributing to the chat, and thus may be a detriment to the network.