On 03/12/2015 08:39, Mike Bird wrote:
> On Wed December 2 2015 23:53:51 Michael Howard wrote:
>> I've been getting hammered by spam so tried a few things, rDNS checks
>> being one of them. Unfortunately, the mail server checks the rDNS for
>> the host (mail.pearsoncomputing.net), the domain alone is not sufficient
>> ( See results from 'mxtoolbox.com' - Your Reverse DNS Record (PTR) is
>> not a valid host name. According to email sending best practices, a PTR
>> Record should be a valid host name. If the PTR Record is not a valid
>> hostname, there is a likelihood that you will experience email delivery
>> issues with anti-spam services.)
> I have been using rDNS checks for as long as I can remember
> and I don't see any problems with TDE lists.  TDE list mails
> arrive here from 192.119.205.242.  rDNS maps this to
> pearsoncomputing.net and DNS in turns maps that back to
> 192.119.205.242 so no problem.
>
> I think you're running into problems checking HELO
> (or EHLO) rather than rDNS.

No, I'm running into problems running rDNS checks. As mentioned above, 
if you put 'mail.pearsoncomputing.net' into the search box at 
'http://mxtoolbox.com/diagnostic.aspx' you will receive a warning from 
the 'SMTP Valid Hostname' test to the effect that 'Reverse DNS is not a 
valid Hostname'. The explanation of the warning, correctly states that;

  'Your Reverse DNS Record (PTR) is not a valid host name. According to 
email sending best practices, a PTR Record should be a valid host name. 
If the PTR Record is not a valid hostname, there is a likelihood that 
you will experience email delivery issues with anti-spam services.'

Mail log extract;

2015-12-02 04:49:35 +0000 08 mail DNR:00000040: '192.119.205.242' found 
PTR 'pearsoncomputing.net'
2015-12-02 04:49:35 +0000 08 mail SMTP-IN:00000040: Reverse DNS check 
failed for <mail.pearsoncomputing.net> connected from <192.119.205.242>
2015-12-02 04:49:35 +0000 08 mail SMTP-IN:00000040: Set smtp explanation 
to [Reverse DNS check failed for <mail.pearsoncomputing.net> connected 
from <192.119.205.242>]
2015-12-02 04:49:35 +0000 08 mail DNR:00000040: Search MX for 
'lists.pearsoncomputing.net'
2015-12-02 04:49:35 +0000 08 mail DNR:00000040: 'pearsoncomputing.net' 
found MX '192.119.205.242' with priority 0

Regards,
Mike.

-- 
Mike Howard
Lancashire
England