> Regarding this problem i contacted some postmasters of these domains.
> At least one answered, that their primary MX record is for internal
> use only and does not accept mail from outside their network ...
They do not have their mail server set up properly. The MX record is an Internet
resource, so any Internet mail server is going to find their primary mail server and
try using it. If they want to play games like that, they can just change their
internal DNS server to point to their internal mail server, and have real DNS point to
the primary mail server.
Technically, I think this is a "legal" setup. However, it is a very, very poor setup
and wastes Internet resources -- colleges should definitely know better.
> In all cases i found in the IMail log files that the response from
> their servers is:
>
> 04:24 09:54 SMTP-(000000BA) 421 SMTP service not available, closing
> transmission channel
That's the Internet equivilant of hanging a sign on your store that says "I'll be back
in 5 minutes" when you retire. In Internet terms, it means "The error condition is
temporary and the action may be requested again. The sender should return to the
beginning of the command sequence." 421 is normally used when a server is about to be
rebooted. RFC821 makes it VERY clear that any response code beginning with "4"
indicates that the remote mail server should keep trying.
They should be returning "554 Transaction Failed: This mail server does not accept
E-mail from the Internet" or some such text along with the 554 numeric code.
It is definitely the fault of the remote mail server, not IMail. They are breaking
the rules, and they have to accept the consequences.
--
-Scott
Declude: Anti-virus and Anti-spam solutions for IMail. http://www.declude.com
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