Re: Lenny/exim4: how to set helo for outgoing SMTP

[Kilian <kil@gnu.ch>]

randall wrote:
>> Kilian wrote:
>>
>>>
>>> Under etch, I just changed helo_data in /etc/exim4/exim4.conf.template
>>> manually - not very nice, but it did what I needed. Now my mailconfig is
>>> broken because some hosts won't accept my mails as the HELO does not
>>> match the IP of the firewall, of course. Is there really no way to
>>> change the outgoing HELO value in exim 4.69-9? I am using the "internet"
>>> config of exim4.
> i am not familiar with Exim, but with postfix i use in my config
> "myhostname = mail.songshu.org"
> there should be something similar with Exim i guess.

Yep, in postfix it really is as simple as setting myhostname in main.cf
- this is the value postfix uses for identifying itself in remote SMTP
sessions, regardless of the DNS record for the host it runs on.

> another option would be to ask your isp to change the PTR record on that
> IP to the  HELO exim uses.

I have a firewall with a public IP and a PTR record for that IP. There
are several hosts behind the firewall with private IP addresses. Some of
them send mails to the internet, so I cannot change the PTR of the
firewall to one of those hostnames. I need exim to identify itself in
the HELO sequence as the PTR record for the firewall; RFC 822 states:

  HELLO (HELO)

   This command is used to identify the sender-SMTP to the
   receiver-SMTP.  The argument field contains the host name of
   the sender-SMTP.

Now to the receiver SMTP, my host appears as the firewall, so IMHO, it
must identify itself with the hostname set in the DNS for the firewall.

[...]
> HELO is for identifying the mailserver, not the domain it sends for.
> there is no reason why the hostname of the mailserver should match the
> domain names of the mails it sends out

I agree.

> if both HELO and the PTR record say mail.server.com there is no problem,
> whatever the domain of the send mail might be.

Exactly, and herein lies my problem...

	-- Kilian