Abstract: In filtering out the receipt by one or more users of mass mailings of unsolicited electronic mail, know as spam, a pass list or whitelist is built of electronic mail addresses to which the user or users send electronic mail. Incoming electronic mail from members of the pass list or whitelist bypasses the filter for unsolicited electronic mail, to avoid a possibility of electronic mail from such known correspondents being mistakenly identified as unsolicited electronic mail by the filter.