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Andy's header has in it: > Received: from 73467.2574.compuserve.com (slip-ppp5.ramsey.nis.net [198.69.26.84]) by arl-mail-svc-1.compuserve.com (8.6.10/8.6.9) with SMTP id WAA22318.; Thu, 4 Jan 1996 22:11:57 -0500 Then he writes: > Ken, it is a known "feature" of the internet SMTP (Simple Mail Transfer Protocol) that most > mail servers will accept outgoing mail from ANY mail client. As long as the message is > properly formatted, the mail server will take it and send it on it's way. The person with > the mail client (e.g. a PC with any of the popular mailers or web browsers) can set ANYTHING > they want in the "from:" field. Randy, I know quite a bit about SMTP mailers and what not. Please note, you're using "nis.net" apparently as your slip/ppp feed in order to use some mail client to send mail. The message from Joel came FROM COMPUSERVE, not an external mail client. > > Even worse, most mail servers (such as mail.compuserve.com) will accept ANY outbound mail > from ANYONE. This message that I'm typing RIGHT NOW is being written while I am dialed into > my regular Internet provider - but I have set up my mail software to route all OUTBOUND mail > to mail.compuserve.com. The CompuServe outbound mail server (like most others) will NOT > require a user id or logon or password so virtually EVERYONE can send "CompuServe" > orginating messages with ANYTHING they want in the UserId. In essence, this message right > now is a "fake" - my IP is currently on the NIS.NET subnet - but I'm posting it through > MAIL.COMPUSERVE.COM. Except I'm faking the from: field to my show my very own CompuServe > ID... Sorry, your IP came through as from the NIS.NET in the message header. 198.xxx. something or other. Explode the header from the techdiver message. Most mail servers have reverse DNS lookup that shows where the message came from. Compuserve apparently has that, since it also shows your IP address as well as domain name (nis.net). > > That is a know security issue on the Internet. Not just is the CONTENT of you mail subject > to hacking, but more importantly, in many cases there is NO way to "authenticate" the send > of a message. That's why conducting business on the Internet has been attempted carefully - > one could order $100,000 worth of goods in SOMEONE ELSES name. Reverse DNS lookups solve that problem. Compuserve does reverse DNS lookups. The message in question was FROM COMPUSERVE, not from anywhere else. > > I hope my message will help you to look at the matter of fake mails with different eyes. > > Best Regards > Andy Schmidt [NJ] Andy I hope you learn more on SMTP yourself. I've been investigating the hell out of the fake message problem, and unfortunatly my mail server doesn't do reverse lookups, thats WHY I moderated the cavers list. Ken -- -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Ken Sallot "I'm not flying. I'm falling, with style" CIRCA - Buzz Lightyear kens@uf*.ed* (352) 392-2007 http://grove.ufl.edu/~ken -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
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