Re: tlug: It works!

[Frank Bennett <bennett@example.com>]

Jonathan Byrne - 3Web <jq@example.com> writes:

> On Fri, 9 Oct 1998, Scott Stone wrote:
> 
> >Received: from ume.pht.co.jp (sstone@example.com [210.171.55.126] (may be forged))
> >	by tlug.linux.or.jp (8.8.8/8.8.8) with ESMTP id LAA00714
> 
> What it is about this that makes the MTA think it might b forged?

Possibly the fact that Scott's pc126.pht.co.jp machine is not
registered publicly for forward DNS lookup.  If I've got this
right, sendmail notices this and suspects that somebody might be
pretending to be Scott, so (as configured) it tacks on a warning.

This is a little odd; it's usually the reverse lookup entry that
gets left out.  There may be a good reason for this arrangement
though.  Security maybe?  Scott, you out there?  (And if so is
that really you?)

Here's the result returned by "nslookup" from our DNS server,
first with reverse lookup:

  > 210.171.55.126
  Server:  nomolog.nagoya-u.ac.jp
  Address:  133.6.33.1

  Name:    pc126.pht.co.jp
  Address:  210.171.55.126

And then with forward lookup:

  > pc126.pht.co.jp
  Server:  nomolog.nagoya-u.ac.jp
  Address:  133.6.33.1

  *** nomolog.nagoya-u.ac.jp can't find pc126.pht.co.jp: Non-existent host/domain
  > pht.co.jp
  Server:  nomolog.nagoya-u.ac.jp
  Address:  133.6.33.1

The server _can_ reach the edge of Scott's domain, however:

  > pht.co.jp
  Server:  nomolog.nagoya-u.ac.jp
  Address:  133.6.33.1

  Name:    pht.co.jp
  Address:  210.171.55.2

Cheers,
-- 
-x80
Frank G Bennett, Jr         @@
Faculty of Law, Nagoya Univ () email: bennett@example.com
Tel: +81[(0)52]789-2239     () WWW:   http://rumple.soas.ac.uk/~bennett/
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