Re: [exim] OT: Daft Question: HELO/EHLO FQDN or FQHN?

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Author: Ian Eiloart
Date:  
To: <exim.ml@riotm.co.uk>
CC: <exim-users@exim.org>
Subject: Re: [exim] OT: Daft Question: HELO/EHLO FQDN or FQHN?
On 17 Apr 2012, at 07:37, Ron White wrote:
>
>
> However, looking at RFC's (821/2821/1123 section 5.2.5) I'm struggling
> to get absolution on it, and fear I may have understood wrong.
>
> 2821 says Syntax:
> ehlo = "EHLO" SP Domain CRLF
> helo = "HELO" SP Domain CRLF


This is clarified in 2.3.5 of rfc2821, and of rfc5321, which both say:

"The domain name, as described in this document …, is the
entire, fully-qualified name (often referred to as an "FQDN"). A
domain name that is not in FQDN form is no more than a local alias.
Local aliases MUST NOT appear in any SMTP transaction."

rfc5321 strengthens this

"The domain name given in the EHLO command MUST be either a primary
      host name (a domain name that resolves to an address RR) or, if
      the host has no name, an address literal…"



--
Ian Eiloart
Postmaster, University of Sussex
+44 (0) 1273 87-3148