Re: ingress SMTP

* Nicholas Suan · * Wed Sep 03 13:26:51 2008

On Sep 3, 2008, at 12:49 PM, Jay R. Ashworth wrote:
On Wed, Sep 03, 2008 at 09:40:20AM -0700, Michael Thomas wrote:

"Allowing unfiltered public access to port 25 is one of the things
that

increases everyone's spam load, and your ISP is trying to be a Good

Neighbor in blocking access to anyone's servers but their own;
many ISPs

are moving towards this safer configuration. We're a good
neighbor, as

well, and support Mail Submission Protocol on port 587, and here's
how

you set it up -- and it will work from pretty much anywhere
forever."

I think this all vastly underrates the agility of the bad guys. So
lots of

ISP's have blocked port 25. Has it made any appreciable difference?

Not that I can tell. If you block port 25, they'll just use another
port and

a relay if necessary.

You're forgetting that 587 *is authenticated, always*.

I'm not sure how that makes much of a difference since the usual spam
vector is malware that has (almost) complete control of the machine
in the first place.