Threading the senderbase reputation needle

Jason Gurtz jasongurtz at
Tue Feb 2 15:21:55 UTC 2010

> Has anyone come up with a reverse DNS 'pattern' that one can employ that
> will prevent Senderbase from assigning a poor reputation to an entire
> because they saw an email they didn't like from a single IP address?
> We're an infrastructure provider, which means that we lease servers, etc
> to customers and everything we do uses static IPs.
> Any advice?

Since email reputation is now being based on the neighborhood theory you
must do one of the following:

Do one of the following (hopefully #1):

1.) Provide custom reverse DNS for the customer.  BCP for SMTP server DNS
is matching forward and reverse DNS.  Anything else is suspect...

2.) Set up a relay host and funnel all customers mail through it.

Side effects of each:

1.) Slightly more work on the front end (but hey, even AT&T will do this
for business DSL customers).  People will know you have clue.  The
technical staff at your customers will be happy and recommend you to their
peers (well, I guess this depends a bit on what kind of customers you

2.) You have taken responsibility for all your customers' outbound mail
flows.  You will need to scale an abuse desk and maintain effective
anti-spam policies (including customer education).  If you don't run an
effective abuse desk (including blocking your own customers outbound mail
when necessary), you will be blacklisted eventually anyway.  You could
charge extra for or outsource this ESP service.


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