Mailing List SIMS@mail.stalker.com Message #11057
From: Bill Cole <listbill@scconsult.com>
Subject: Re: rejected mail
Date: Mon, 17 Jun 2002 20:17:06 -0400
To: SIMS Discussions <SIMS@mail.stalker.com>
At 9:55 PM +0900 6/17/02, Andrzej Kozlowski  imposed structure on a stream of electrons, yielding:
On Monday, June 17, 2002, at 02:08  AM, Bill Cole wrote:
It looks like mail.flaschcom.com doesn't accept mail coming from platon.c.u-tokyo.ac.jp.

Given the significant amount of spam flowing through *.jp machines, this is not a big surprise. I know that is a very gross way to do rejections, but it works reasonably well for many organizations: just reject anything coming from all of a country, and the spam coming from there will stop. For most US ISP's, the amount of legitimate mail coming from japan is extremely small.



-- Bill Cole
bill@scconsult.com


It can't be that they reject all mail coming form Japan because they accepted the same message sent form another server  in Japan (my dialup ISP's). Moreover, ac.jp is a university domain (just like .edu) so I guess most people would consider it less likely to be a source of spam.

Not really.

Schools in Korea, Japan, Taiwan, and Thailand make up a big slice of my spam sources, largely due to misconfigured proxies. Most of that spam actually originates (apparently) in the US.

Also, for some people (myself included) the volume of actual Japanese spam in Japanese with .jp return addresses has made it useful to


(One curious thing: living in Japan I never, ever receive any spam form Japanese domains. It may sound amazing but it is true.  However I do receive a lot form Korea, Taiwan, China and of course USA.)

Returning to my original question, perhaps Ron's explanation

On Monday, June 17, 2002, at 02:30  AM, Ron Risley wrote:

It is possible that the receiving MTA is checking that your SIMS machine's IP address resolves to the SIMS host name. There are a number of reasons why this is poor practice, but there are a significant number of MTAs that behave that way.

might be closer to the mark if I could only understand what it means. My SIMS machine IP address is 157.82.45.169 an it resolves to platon.c.u-tokyo.ac.jp. Is there anything unusual about this?

No, that's fine, and probably what Ron meant.

 Or could it all be somehow connected with the fact that my client from which the mail originates is actually in a different domain than the SIMS machine?

Not if I'm interpreting that bounce correctly. It looks like all the flashmail.com machine had to base a rejection on was your return address, the target address, and where the connection to it came from.  To figure out the original source, it would need to have gotten the message itself with headers and done some trace work that is so uncertain as to be absurd for any MTA to attempt.

It is slightly possible that they would reject a message if the return address didn't seem to make sense with the connection source, but that is also an extremely unreliable sort of check and so is only used by a small number of sites that really don't care much about getting mail.

The only people who can give you a certain answer are the people running flashmail.com.


--
Bill Cole                                  bill@scconsult.com

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