On Fri, Feb 19, 2010 at 8:35 PM, Larry Sheldon <LarrySheldon@cox.net> wrote:
On 2/19/2010 7:20 PM, William Herrin wrote:
"If an SMTP server has accepted the task of relaying the mail and later finds that the destination is incorrect or that the mail cannot be delivered for some other reason, then it MUST construct an "undeliverable mail" notification message and send it to the originator of the undeliverable mail (as indicated by the reverse-path)."
Does the RFC say what to do if the reverse-path has been damaged and now points to somebody who had nothing what ever to do with the email?
Hi Larry, Re-reading the paragraph I quoted and you repeated, I'm going to say that the answer is "yes." SMTP had been around for a long time when 2821 was written, as had spam. I doubt leaving the "must" in section 3.7 was an oversight. Even if it was, I didn't suggest rote adherence to the RFC. I said, "reasonably compatible with RFC 2821's section 3.7." Dropping all bounce messages on the floor -- the exact opposite of 3.7 -- is not "reasonably compatible."
Do your SNMP clients respond truthfully to EXPN requests?
I assume you mean "SMTP servers" here rather than "SNMP clients." 2821 rightly leaves EXPN as a "should" instead of a "must." And yes, they respond truthfully -- with an prohibited operation error.
I don't run any sites anymore, but when I did, unsolicited traffic (traffic not in response to traffic from somebody on my network) was blocked when detected, and remained blocked until somebody inside our boundary complained, and on second occurrence until my management directed me to remove the block.
I can't resist the set up: Maybe that's why you don't run any sites anymore. Regards, Bill Herrin -- William D. Herrin ................ herrin@dirtside.com bill@herrin.us 3005 Crane Dr. ...................... Web: <http://bill.herrin.us/> Falls Church, VA 22042-3004