[Slackbuilds-users] MTA used by submission form doesn't use FQDN in HELO

Sebastian Arcus s.arcus at open-t.co.uk
Thu Jan 18 09:10:57 UTC 2018

On 17/01/18 23:57, Rob McGee wrote:
> On Wed, Jan 17, 2018 at 05:02:01PM +0000, Sebastian Arcus wrote:
>> The submission form at SBo does a check on the email address to the
>> originating MTA when a package is uploaded.
> The check is done at the MX for the domain, specifically.
>> However, the MTA used by the submission form uses just
>> "slackbuilds.org" as HELO name. I know the RFC only recommends,
>> not requires, a FQDN for smtp HELO names,
> (Note, there is no MTA involved.  This is just a simple PHP form
> attempting to validate the email addresses it is given.)
> FQDN as HELO is required, but indeed "slackbuilds.org" is a FQDN. 

I might be misinterpreting things, but all docs I looked up so far seem 
to imply that a FQDN should include the hostname - and whenever FQDN is 
mentioned, usually it includes the hostname. After all, FQDN's are used 
to identify hosts. "slackbuilds.org" is just the domain part. But maybe 
there is a nuance which I'm missing here. Or you could take the view 
that a domain name can be used as a hostname at the same time.

>> I just tried to upload a package update at SBo, and had my email
>> address rejected, as my own email server, in turn, rejected the
>> connection attempt from SBo. I temporarily disabled the relevant
>> check in my config,
> Would you mind telling me what you did that rejected this?  Also
> please share your MTA logs of the rejection.  Offlist is fine if
> you're shy about posting logs here.

I use Exim with a custom ACL, which checks the HELO for a full FQDN, 
including a hostname, not just the domain. As stated in my original 
post, the script/form is not technically breaking any standards - it was 
just a suggestion.

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