With my limited knowledge of such things, it seems like a lot of spam could be prevented by blocking all mail that does not contain a simple keyword. This keyword could be included in the footer of all mail going to the list as a reminder. It could even change from time to time.
Have I overlooked something? Peter -- SLUG - Sydney Linux User's Group - http://slug.org.au/ More Info: http://lists.slug.org.au/listinfo/slug
