[Info-vax] Decuserve.org - Anyone know why it's down?

[Stephen Hoffman]

On 2015-01-06 17:04:15 +0000, JF Mezei said:

> On 15-01-06 10:12, Bill Gunshannon wrote:
> 
>> That is what we are talking about.  The A and PTR must match or the
>> system is mis-configured or spoofing and mail should not be accepted.
> 
> Nop.  Multiple A records may point to a single PTR which means the one
> PTR for an IP address may not necessarily point to the host name being
> used to send email. Consider multi-homed email server that handles many
> domains.

A multi-homed email server that provides email services for many 
domains has one A record and one PTR record, and zero or more MX 
records.  That mail server will initiate its outbound SMTP connections 
using its own host name, and which has a matching PTR.   If PTR for 
that address does not match, then the mail server can be 
(mis?)classified as a spam engine.


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