On Fri, Jun 19, 2009 at 02:58:14PM -0500, Kyle Wheeler wrote: > On Friday, June 19 at 06:33 PM, quoth Rocco Rutte: > > Even if the messages comes in through SMTP, a server could check the > > presence of Received: headers to determine if he's the place where > > delivery starts. > > That's a good heuristic, but I don't think that that's definitive. It's not a good heurisitc at all... Spammers routinely add Received headers to their messages so that it seems like they are originating elsewhere. Any badly-behaved MTA could "forget" to add them, for whatever reason (including just being buggy). > I suppose another way of putting it is: since it's entirely possible > to receive a message that does not have a Message-ID header (e.g. an > email server that obeys RFCs 821 and 2821 but not 5821... This is a fairly imporant point. Said another way, just because something is an RFC, doesn't make it gospel. Said yet another way, even if an RFC has been branded a standard, there will be implementations in the real world which predate the standard, and therefore do things the old way, FOR YEARS AND YEARS TO COME. You can't assume that everyone (or anyone, for that matter) follows the RFCs. -- Derek D. Martin http://www.pizzashack.org/ GPG Key ID: 0xDFBEAD02 -=-=-=-=- This message is posted from an invalid address. Replying to it will result in undeliverable mail due to spam prevention. Sorry for the inconvenience.
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