SMTP authentication for broadband providers

Wed Feb 11 20:19:01 UTC 2004

On Wed, Feb 11, 2004 at 03:13:30PM -0500, Sean Donelan wrote:
> On Wed, 11 Feb 2004 Valdis.Kletnieks at vt.edu wrote:
> > On Wed, 11 Feb 2004 11:15:20 PST, Dave Crocker said:

> > > what about port 25 blocking that is now done by many access providers?
> > > this makes it impossible for mobile users, coming from those providers,
> > > to access your server and do the auth.

> > Port 587.
 
> So is it time for ISPs to start blocking port 587 too?

> If the complaints are going back to the IP address anwyay, why shouldn't
> an ISP force it subscribers to go through the ISPs mail servers so it can
> control any messages sent by its subscribers?

My understanding is that in most cases, providers are blocking port 25
outbound to prevent direct to MX spamming from their customers' machines
- not to prevent customers from sending mail through other providers'
mail servers. Unless they're specifically trying to force people to use
their mail servers (which I don't think is usually the case), they don't
need to block port 587.

-- 
"Since when is skepticism un-American?
Dissent's not treason but they talk like it's the same..."
(Sleater-Kinney - "Combat Rock")