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Thread ID: 42984	2004-02-28 21:09:00	E-mail Server Tech Question	Perry (4966)	Press F1

Post ID	Timestamp	Content	User
218864	2004-02-28 21:09:00	A fairly "deep" technical question about e-mail servers. (Deep for me, anyway!) If I send an e-mail and have one character wrong in the individual’s name (i.e. not in the domain name), e.g. matthewk@fiction.com (two Tees), the correct address being mathewk@fiction.com (one Tee), my understanding is that such an e-mail will get "out" OK through my ISP’s (originating) mail server (because it sends to a valid/registered domain name, not to an individual) and "in" OK to the intended destination domain mail server. Once there, however, the destination mail server will check the individual name, determine that it is invalid, then reply/return the message with a system-generated delivery failure notice, with some comment like "Sorry, no mailbox here by that name." However, if I get the domain name wrong, my ISP’s mail server will detect this, and, without even attempting to on-send my e-mail, will auto-generate a reply/return the message to me with a system- generated delivery failure notice like: "This address has permanent fatal errors." I hope I’ve described that well enough that the questions are clear. How close am I to being correct in my assessment?	Perry (4966)
218865	2004-02-28 22:04:00	Thats how it works for me. Anything sent to my domain gets through. Then its up to me to decide what to do with it. Some domains may contract with the ISP for "mail bagging" services, which could modify this behaviour? Anything with an incorrect domain doesn't come to me, and if the domain does not exists you get the ISP return.	godfather (25)
218866	2004-02-28 23:16:00	Yep that's how it works your ISP will valiadate that the mail can be sent to the domain name but the user address is handled by mail server. If it's a hotmail type or ISP mail account then that server will respond for corporate accounts you will recive a message from that server. However sometimes you can set up alas's for common misspellings of particular users so your mail will get through anyway. There are a few other things to consider - sometimes a company will block mail from a particular domain or ISP as it may be spam or reject mail with certian attachments such as large images exe etc.	me_ill (5233)
218867	2004-02-28 23:20:00	What do you mean by: "Some domains may contract with the ISP for 'mail bagging' services, which could modify this behaviour?" This is something to do with the relationship between a domain+server (one thing: right?) and the means by which it connects to the web?	Perry (4966)
218868	2004-02-28 23:29:00	This is not idle curiosity, but checking on something told to me by someone else . And that 'something' just didn't sound right . Here's what was proffered as an explanation for a 3-4 month delay in receiving an e-mail delivery failure response . Based on what contributors here are saying, I think a reality check is needed by the person who sent this, or the IT manager who told him this . . . "The delivery failure receipt for the e-mail you sent to DeeKnee is controlled by your Internet Service Provider and is not a function of our systems . As the IT manager explains it to me it is your ISP that is endeavouring to deliver the message and therefore needs to notify you if it is unable to do so . The delay is unusual but we are unable to explain it . " That communication came from another person at the same domain name, so I know that the earlier failures were because I spelled DeeNee without the "K" However, four months to generate a "no mailbox of that name" type response?!?!? (A quasi government department, unfortunately) Anyway, on the basis of comments so far, the explanation (italicised, above) given doesn't seem to be valid, does it?	Perry (4966)
218869	2004-02-28 23:38:00	> What do you mean by: "Some domains may contract with > the ISP for 'mail bagging' services, which could > modify this behaviour?" If I contract with say, clear.net to handle my mail for my domain, I could also allow them to test for valid users @ my domain and contract as to how invalid emails were processed by them (i.e. dumped, returned or forwarded). My reference to "some domains" is to the owner of those domains. These are commercial issues agreed by the parties involved and could affect the behaviour that you may expect. There is no hard rule in those cases, and any agreements are commercially sensitive so you will not find out from the ISP. Just as some domain owners may dump all unrecognised user addressed email and not have it vetted by their postmaster. You will never know.	godfather (25)
218870	2004-02-29 01:16:00	The domain name is checked. It is sent to a DNS server . Only if the spelling matches that of a host in the hierarchical DNS will the mail sender get an IP address to send the mail to. It might not be the right destination (depending on your spelling) , but it will be a valid destination.;-) What happens at that destination depends on the way the mail processing software has been configured. Some send any mail with unknown addressees to a "postmaster", who will see what can be done. Whoever is lumbered with the postmaster alias usually has other, real, work to do. Some systems(most, these days, with spam and other junk?) will bounce it with an appropriate error code. I suppose it depends on how important incoming mail is considered. You might want to handle customers carefully.;-)	Graham L (2)
218871	2004-02-29 01:57:00	Looking at the "bounce" server response, this is what it said: This is an automatically generated Delivery Status Notification. Delivery to the following recipients failed. dee.nee@questionable.co.nz I had spelled only the mailbox name incorrectly. The domain name was correct. So, it is possible that my wrongly addressed e-mail languished in the "postmaster's" mailbox, until it came to the top of the to-do list, right? But - no matter what - such was not a function of my ISP, was it? It was a function of the destination domain name server/administration or that domain name's ISP, depending on the contractual arrangements that had been set up - right?	Perry (4966)
218872	2004-02-29 02:37:00	That would be handled by a not-found redirect to Postmaster, with a daemon which runs every so often to bounce any which get there. It's definitely not your ISP. It might be the the mailserver of the ISP of the destination; it might be a mailserver owned and run by the destination.	Graham L (2)
218873	2004-02-29 02:40:00	Thanks. Even if I struggle just a little with some of the other concepts I can be sure that it is not a function of my ISP.	Perry (4966)
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