Re: Networking -- use of two Internet connections for one server with round robin DNS -- web okay, but should I do mail this way too?

[Bob Proulx <bob@proulx.com>]

Brian wrote:
> Stan Hoeppner wrote:
> > They're not properly setup if they have a dynamic IP address, and most
> > xDSL customers get a dynamic IP.  Given that 95% of all email is spam,
> 
> What is improper (technically incorrect) in the setup when sending email
> from a dynamic IP address?

It is one of practicality.  If you can identify a spammer then you can
block them.  Therefore to prevent blocks spammers try their best to
move around as much as possible.

Basically static IPs have a reputation associated with them.  I can
learn to trust or not to trust any particular IP address.  But dynamic
addresses are effectively anonymous.  They are faceless zombies and
endless in number.

A botnet army exists on virus infected machines almost singularly for
the purpose of sending spam.  They can attack you from literally a
thousand different IP addresses.  It isn't possible to blacklist them
because they get one IP address today and a different IP address
tomorrow.  All they need to do to defeat the blacklist is to obtain a
new address and move to it.  And there is a very large number of them.

But guess what?  All of those IP addresses exist in dynamic IP blocks!
By blocking mail from dynamic IP blocks I can block almost all of the
spam that attacks me.  Therefore it is one of practicality.

If you are going to send email then you need a static IP address.  It
is one of reputation and in this case the reputation is attached to
the IP address.  It is the only thing we have to grip upon.

Bob

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