ietf-smtp
[Top] [All Lists]

Re: RFC2821, section 4.1.1.1 and HELO/EHLO

2004-01-02 16:14:27
On Fri, 02 Jan 2004 17:41:26 EST, you said:
First, the ABNF is wrong given the text and, on behalf of myself 
and the several people who checked it, my/our apologies.

A separate issue comes to mind - a number of systems reject the
format mentioned in 4.1.1.1.  In particular, Sendmail 8.12.4 included
this change:

        If AllowBogusHELO is set to false (default) then also complain if
                the argument to HELO/EHLO contains white space.  Suggested
                by Seva Gluschenko of Cronyx Plus.

Such sendmails reject it:

Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
220 turing-police.cc.vt.edu ESMTP Sendmail 8.13.0.PreAlpha5/8.13.0.PreAlpha5; 
Fri, 2 Jan 2004 18:08:03 -0500
ehlo [127.0.01.1] test.domain.name
501 5.0.0 Invalid domain name

(Which incidentally was how I opened this can of worms to begin with).

Fortunately, at least Sendmail allows retrying with a less-weird EHLO, so
there's a way for future systems to drop back.  Unless of course some system
out there gets annoyed at seeing a second EHLO instead of a HELO drop-back.

Isn't backward-combatability fun?

Attachment: pgp5GBIuV5xCm.pgp
Description: PGP signature