OOT: Mail rejected with bogus helo

[Steve Freegard]

Hi Budi,

Budi Febrianto wrote:
> Dear All,
> 
> I know this OOT, but because many sendmail experts in here, I give it a 
> shot.
> 
> I'm using sendmail-8.13.8-2.el5 with MailScanner 4.65.3.
> 
> Whenever my users sent emails to certain domains, it will rejected with 
> this error.
> 
>  >>>>>
> 553 yyy.yyy.yyy.yyy rejected due to spam, contact 555-505-5555 (bogus 
> helo xxx.xxx.xxx.xxx)
>  >>>>>
> 
> I'm not sure what happen, because I don't have the same problem with 
> others domain.
> 

RFC2821 states that the HELO should either by a FQDN or an IP-domain 
literal (e.g. [ip.ip.ip.ip]) so a bareword IP address in the HELO that 
is not in square brackets is not valid.

So - if you are sending "HELO ip.ip.ip.ip", then that isn't valid, but I 
don't think it's possible for Sendmail to sent a HELO in this format as 
it always does the right thing.

The command 'sendmail -d0.5 < /dev/null' will show you all the name 
variations that sendmail would use in a HELO argument.

I suspect however that in this case it's simply a lame spam filter 
that's causing you an issue.  Feel free to mail me directly to my 
@fsl.com which has strict-helo filtering amongst other things, so being 
able to mail me directly without getting an SMTP-time rejection would be 
a good way to prove it.

Cheers,
Steve.