Re: RES: Email oddity

[Ken Sims <mdrg8066@xxxxxxxxxxx>]

Hi Dennis -

On Fri, 13 May 2011 13:25:52 -0400, Dennis <iseries@xxxxxxxxxxxx>
wrote:

> If they are like many others who use this technique, they simply want to know that (both) :
> > the IP  address can be resolved to a host
> > that host is not  generic name like those assigned by ISPs for dialup and the like.

Let's not forget also that after

> the IP  address can be resolved to a host

comes

> the host name resolves back to that same IP address.  (It can also
legitimately resolve to additional IP addresses.)

Personally I don't implement any of these requirements on my personal
mail server.  There are too many clueless ISPs and too many clueless
admins.

For example, a hosting company, which is multi-homed and controls
their own DNS and rDNS, sent me an email where the rDNS host name did
not resolve to the IP address.  (It wasn't spam.  It was a billing
notification for my sister's domain which is hosted there but which I
pay for.)

Ken
Opinions expressed are my own and do not necessarily represent the views 
of my employer or anyone in their right mind.