Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!usc!snorkelwacker.mit.edu!stanford.edu!agate!bionet!turbo.bio.net!lear From: lear@turbo.bio.net (Eliot) Newsgroups: comp.mail.misc Subject: Re: Interesting header/error message Message-ID: Date: 17 May 91 21:40:18 GMT References: <1991May13.033329.24202@chinet.chi.il.us> <1991May13.112332.20564@oar.net> Organization: GenBank Computing Resource for Mol. Biology Lines: 34 karl.kleinpaste@osc.edu writes: >Rayan's mailer is unquestionably to be awarded Most Picky Mailer Ever >Devised, but it has the good taste to deliver anyhow, in view of the >wide disregard for this particular bit of syntactic pedanticism. The above situation is a recipe for disaster. Imagine, if you will, a message sent to a very large international mailing list with a completely trashed To: header, but with the envelope intact. What is a mailer to do? [a] Bounce the message as undeliverable. [b] Continue to process the message, possibly logging an error. [c] Continue to process the message AND send an error to the sender. If you said [c], that's what sendmail does; and it's wrong. There was an excellent example of this exact problem last week (see Erik Fair's note to a bunch 'o lists including tcpip and risks). The message caused every sendmail that touched it to send an error message back to the sender, in some cases multiple times. Distributed systems are funny that way. If you said [a], I'd argue that you're still wrong, so long as the message will remain in an environment where an envelope exists, as you would be violating the robustness principle. That leaves [b] (preferably logging an error message). -- Eliot Lear [lear@turbo.bio.net]