Why do so few mail providers support Port 587?

Wed Feb 16 03:41:52 UTC 2005

<dons ISP hat>

We get sick of blocking ports.

We're little guys. About 10,000 users. Yesterday, we blocked 11025 
connections either inbound to addresses that aren't mail servers, or 
outbound from addresses that aren't supposed to be mail servers.

This is a case of those that know a little too much praying on those 
that don't know quite enough with those that don't have enough of 
anything trying to stop it from happening.

I can't flame you. I fully agree with you. But until I can find a way to 
stop the Big Bad Wolf from huffing and puffing, the house will be made 
of bricks, and the door will be locked.

Bob Martin

Erik wrote:
> I just get sick of providers blocking traffic...their job is to PASS
> TRAFFIC.  There must be a better solution, but laziness is getting the
> better of us all, as usual.
> 
> We've had so many problems with "IP Providers" blocking various "IP
> PROTOCOLS" that we've just ended up forcing all of our users to use VPN
> tunnels for everything...except when the providers block that!!!  Then
> we're just screwed.
> 
> Anyways, just my two cents...
> 
> Please don't flame me, I'm just a lowly network guy....:)
> 
> 
> 
> - Erik
> 
> -----Original Message-----
> From: Sean Donelan [mailto:sean at donelan.com] 
> Sent: Tuesday, February 15, 2005 8:00 PM
> To: nanog at merit.edu
> Subject: Why do so few mail providers support Port 587?
> 
> 
> Although RFC2476 was published in December 1998, its amazing how few
> mail providers support the Message Submission protocol for e-mail on
> Port 587.  Even odder, some mail providers use other ports such as 26 or
> 2525, but not the RFC recommended Port 587 for remote authenticated mail
> access for users.
> 
> Large mail providers like AOL, GMAIL and Yahoo support authenticated
> mail on port 587; and some also support Port 465 for legacy SMTP/SSL.
> But a lot of universities and smaller mail providers don't.  They still
> use SMTP Port 25 for roaming users.  With AT&T, Earthlink, COX, Netzero
> and other ISPs filtering port 25 for years, I would have thought most
> mail providers would have started supporting Port 587 by now.
> 
> What can be done to encourage universities and other mail providers with
> large roaming user populations to support RFC2476/Port 587?
> What can be done to encourage the mail client software programers (i.e.
> Outlook, Eudora, etc) to make Port 587 the default (or at least the
> first try) and let the user change it back to port 25 (or automatically
> fallback) if they are still using a legacy mail server.
> 
> Sendmail now includes Port 587, although some people disagree how its
> done.  But Exchange and other mail servers are still difficult for
> system administrators to configure Port 587 (if it doesn't say click
> here for Port 587 during the Windows installer, its too complicated).
> 
> 