[OT] sendmail HELO

[Roland Ehle]

Hi Mark,

Mark Nienberg schrieb:
> For messages from mail daemons, which don't use "envelope from", SPF resorts to
> using the address given by the HELO of the sending machine.  So my questions are:
>
> 1. How can I test what my sendmail is using for its HELO when it sends mail?  Is it
> the same name that is listed in the "Received:" headers?  Is it the same name that I
> see when I telnet to port 25 on the server? Do I have to resort to an ethereal capture
> or something?  I suspect it is using its own machine name, which is an internal name
> that does not have a real DNS record.  I should probably correct that.  I could make it
> match the name used in the MX record for our domain, for example.
>
> 2. If I have to correct it, is it done with a line like this?
>
> define(`confDOMAIN_NAME', `mail.mydomain.com')dnl
>
> 3. Alternatively, I guess I could get our ISP to set up a DNS record for whatever
> name that the machine is using.  Are there any implications one way or the other?

sendmail uses either the local hostname or, if defined, the value in
sendmail.cf:

# my official domain name
# ... define this only if sendmail cannot automatically determine your
domain
#Dj$w.Foo.COM

But, in addition, you should have your ISP set a correct PTR-Record for
the IP address your mailserver uses, because recipients mailserver do a
reverse lookup.

Regards,
Roland