iis smtp nntp: Mail Hoping around our SMTP Servers -- iis smtp nntp

Mail Hoping around our SMTP Servers

Harjinder Singh
8/24/2004 10:39:38 AM

iis smtp nntp: We currently have three SMTP Servers in our network, each server serving
it's own websites/applications.

A strange hop of email is occuring within the servers, which i cannot find
the source of.

Assume Server A sends out an email to an undeliverable domain. For whatever
reason, the return email will come back to my account from Server B, stating
that the email was underliveable.

Serer C is in a remote location, however we do have a private VPN connection
to our internal network. Server B which is in our internal network will
attempt to send out email and Server C will return the undeliverable
message.

Has anyone else experienced this problem?

Does anyone know why this would occur?

Thanks.

Re: Mail Hoping around our SMTP Servers

Ken Schaefer
11/21/2004 11:16:36 PM

a) Is the "undeliverable" message being generated by the local SMTP server
(in response to a 5xx status code by the remote server)? If so, then the
local SMTP server (eg ServerA) will look in the DNS to determine the MX
record for @yourdomain.com where your POP3 mailbox is, and send the delivery
report there. Presumably this is your internal DNS (eg AD integrated DNS)

b) If the "undeliverable" message is being generated separate by the remote
domain's SMTP server, then it is looking in the external (public) DNS to
work out where to deliver mail for @yourdomain.com, which presumably is
ServerB (or you may have some public gateway SMTP server that is forwarding
mail to your ServerB).

Cheers
Ken

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