first three mails omitted received(qmail invoked from network) may : : - receivedfrom unknown (helo pismtp - prod phx secureserver net((envelope-sender by plsmtp - prod phx secureserver net (qmail- with smtp for may : : - more deleted receivedfrom by smtp mailmt com (argosoft mail server net for thu may : : - fromeric the half bee@aol com datethu may : : - subjecta tonobody in particular@marketing com message-idx-fromip -nonspamnone spamspam and eggsspamspamand spam bye once againthoughdon' do this unless you have good cause this demonstration is intended only to help you understand how mail headers factor into email processing to write an automatic spam filter that deletes incoming junk mailfor instanceyou need to know some of the telltale signs to look for in message' text spamming techniques have grown much more sophisticated than simply forging sender and recipient namesof course (you'll find much more on the subject on the web at large and in the spambayes mail filter written in python)but it' one common trick on the other handsuch to address juggling may also be useful in the context of legitimate mailing lists--the name of the list appears in the "to:header when the message is viewednot the potentially many individual recipients named in the send-mail call as the next section' example demonstratesa mail client can simply send mail to all on the list but insert the general list name in the "to:header but in other contextssending email with bogus "from:and "to:lines is equivalent to making anonymous phone calls most mailers won' even let you change the from lineand they don' distinguish between the to address and header line when you program mail scripts of your ownthoughsmtp is wide open in this regard so be good out thereok client-side scripting