Table 1. Minimum maximums mandated by RFC821 Dan Sugalski "Sending Mail Without Sendmail" The Perl Journal, Summer 1999

Username: 64 characters Domain: 64 characters Path: 256 characters Command Line: 512 characters (including the command and the CRLF terminator) Reply line: 512 characters (including the status code and the CRLF terminator) Text line: 1000 ccharacters (including the CRLF terminator) Max # of recipients: 100