Re: [Exim] IP address in Received headers..

Kevin Sindhu wrote (on 10 Sep 2001 at 18:04):

> Please observe the following header:
>
> Received: from [202.144.239.148] (helo=lima) by mail.open-
systems.org
> with esmtp (TLSv1:DES-CBC3-SHA:168)
>
> The machine here advertises as lima (from helo). However lima
is not a
> complete or FQDN name.
>
> 1) Is this valid?
> 2) If lets say the machine advertises as HELO=lima.foo.com, but
> there's no valid A or AAAA record for lima.foo.com. Is this a
valid
> behaviour or is the sending machine breaking the RFC?

RFC 821 just called for a host name, but RFC 2821 asks for an
FQDN "if available":

4.1.1.1 Extended HELLO (EHLO) or HELLO (HELO)
These commands are used to identify the SMTP client to the SMTP
server. The argument field contains the fully-qualified domain
name of the SMTP client if one is available. In situations in
which the SMTP client system does not have a meaningful domain
name (e.g., when its address is dynamically allocated and no
reverse mapping record is available), the client SHOULD send an
address literal (see section 4.1.3), optionally followed by
information that will help to identify the client system.

(end quote)

If my LAN mail relay were only allowed to accept mail from FQDNs,
I'd have to switch to carrier pigeons.

T.