Recipient email servers looking for source domain entry??

[Jim Picerno]

Thanks for responding. Apparently it was a DNS issue.

On Mon, 6 Mar 2000, Mathias Koerber wrote:

> On Sun, 5 Mar 2000, Jim Picerno wrote:
> 
> | Date: Sun, 5 Mar 2000 19:55:09 -0800
> | From: Jim Picerno <jpicerno at speakeasy.org>
> | To: comp-protocols-dns-bind at moderators.isc.org
> | Newsgroups: comp.protocols.dns.bind, microsoft.public.windowsnt.dns
> | Subject: Recipient email servers looking for source domain entry??
> | 
> | I'm using Exchange 5.5 and I'm gettng the error messages I've listed below.
> | Are these errors referring to a specific DNS entry or is it some other
> | problem with DNS. If there is a specific DNS entry could someone provide an
> | example?
> 
> The first. Many mailservers these days expect that the sender (SMTP MAIL FROM)
> use an existing domain, so that errors etc can be sent back. FOr this
> they perform the usual MX (and A) record lookups.
> 
> While the initial intent for this may have been to just ensure that errors
> during the delivery can actually be sent to the originator, it is often used
> as a means to filter non-existent (and thus likely forged) addresses
> used in SPAM.
> 
> Note that the error you received below is a 4xx error, and thus temporary. This
> usually means that the mailserver was not able to verify the domain
> (due to network problems etc) and that the sending system (yours) should
> retry sending the same mail again later. Had it received an authoritative 'domain does not exist'
> from the DNS lookup, it would (likely) have returned the mail with a 5xx (permament) error.
> 
> HTH
> HAND
> 
> | 
> | 
> | Event Type: Warning
> | Event Source: MSExchangeIMC
> | Event Category: SMTP Interface Events
> | Event ID: 4030
> | Description:
> | The following message could not be delivered to <Jane_Doe at Destination.com>
> | Delivery will be retried later. The  destination server reported: 450
> | <John_Doe at Source.com>: Sender address rejected: Domain not found From:
> | <John_Doe at Source.com> Subject: ABC123
> | 
> | Event Type: Warning
> | Event Source: MSExchangeIMC
> | Event Category: SMTP Interface Events
> | Event ID: 4090
> | Date:  3/5/2000
> | Time:  4:12:52 PM
> | Description:
> | Mail could not be delivered to 123.456.789.10 (Destination.org). The
> | destination server reported 451 <John_Doe at Source.com>... Sender domain must
> | resolve. Delivery will be retried later.
> | 
> | 
> | 
> | 
> 
> Mathias Koerber	  | Tel: +65 / 471 9820    |   mathias at staff.singnet.com.sg
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