Subject: smtpupd-09 prohibits dumb clients

From: "D. J. Bernstein" <[email-masked]>
Date: 29 Jan 1999 04:16:14 -0000

Section 5 of this document requires that clients follow the usual

                   MX lookup                A lookups
   target domain ------------> host names ------------> IP addresses

procedure.

This prohibits the behavior of many existing hosts. Part-time dialup
hosts and dumb clients deliberately skip MX lookups, and sometimes all
DNS lookups. They start from preconfigured host names or IP addresses.

Section 2.1 allows clients that use preconfigured target domains, but
those clients are still required to do MX lookups.

---Dan

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From: Eliot Lear <[email-masked]>
Date: Fri, 29 Jan 1999 08:57:40 -0800

There is a rule about *ANY* IETF protocol that you are ignoring, Dan. 
Any pair of consenting adults can do whatever they want.  More
specifically, the behavior of "dumb clients" talking directly to a
prearranged SMTP server is just that- prearranged.
-- 
Eliot Lear
[email-masked]

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From: Paul Overell <[email-masked]>
Date: Fri, 29 Jan 1999 18:18:16 +0000

In article <[email-masked]>, Eliot Lear <[email-masked]>
writes
>prearranged SMTP server is just that- prearranged.

I agree with Dan here.  Section 2.1 discusses SMTP clients that have 
an "intermediate destination".  Such clients "may otherwise conform to
this specification but are not considered fully-capable".

However, section 5 does not allow for non fully-capable clients as it
requires MX lookups.

Here in the UK it is common for dial-up to use pre-configured "smart
hosts" for all users' mail and for their SMTP clients not to do any MX
lookups.  Such clients should not be deemed by RFC821bis to be non-
conformant.  Section 5 needs to allow for this.
 
Regards
-- 
Paul Overell                                        T U R N P I K E  Ltd

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From: "D. J. Bernstein" <[email-masked]>
Date: 30 Jan 1999 03:41:40 -0000

Eliot Lear writes:
> Any pair of consenting adults can do whatever they want.

But the question for DRUMS is whether they're complying with 821bis.

An smtpupd-compliant client is allowed to relay all messages through
A(MX(mail.isp.gov)). But it isn't allowed to relay all messages through
A(mail.isp.gov) or through a preconfigured IP address. This is silly.

---Dan