Following describes the format of .rec files, which are located in the mail server root directory, and contain the information about disallowed IP addresses (disallip.rec), trusted IP addresses (trstip.rec), banned IP addresses (bannedip.rec). Files are a sequence of following records: TRuleType = (rtRange, rtMask); TIPRuleRec = packed record Version: Integer; Reserved: array[0..15] of Char; RuleType: byte; Str1: string[16]; Str2: string[16]; end; Integer takes 4 bytes. Version is currently not used,and is 0. Char takes 1 byte. RuleType is a byte, which is 0 if a rule is range, and 1 if rule is a mask. For range, Str1 contains the lower value of range, Str2 - the higher value. For mask, Str2 is not used. About Pascal strings: string[n] takes n+1 bytes. 0th byte of a record is an actual length of string. For example, string[6], which contains the string "test" (without quotes) will be represented as 04 74 65 73 74 00 00 Last two 00 00 can be any random value.