Re: FQDN via DHCP, then used in exim4
On Thu, 16 May 2013 09:02:57 +0100
Klaus Doering <klaus.doering999@gmail.com> wrote:
>
> The RaspPi (running Raspbian, a version of Wheezy for the ARMHF
> architecture) also acts as a mail server, talking
> SMTP to the wider world using exim4. After I got an error message
> from some strict server telling me
>
> 504 5.5.2<rpi>: Helo command rejected: need fully-qualified hostname
>
>
> I noticed that exim does NOT use the DHCP-provided domain name.
> The unqualified host name is set in /etc/hostname, and in /etc/hosts
> I intentionally did not set the external IP or
> domain name.
>
Apart from any other issue, please note that the HELO string provided
by your mailserver really needs to be a hostname which can be resolved
in *public* DNS. On the assumption that you're not running your own
public DNS server, then you will need an A record with your domain
host. It's easiest if you use the same A record your MX points to,
though it's not necessary.
Not all mail servers will require their senders to have a resolvable
HELO, but many will, including my exim4. It's disabled by default, I
think, but it's a useful spam reduction technique. Oddly, some of the
pickiest servers now seem to be Exchange installations.
--
Joe
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