nanog mailing list archives

Re: Why do so few mail providers support Port 587?


From: Frank Louwers <frank () openminds be>
Date: Fri, 25 Feb 2005 11:35:33 +0100


On Fri, Feb 25, 2005 at 02:30:01AM -0500, Jim Popovitch wrote:

On Thu, 2005-02-24 at 23:36 -0500, Valdis.Kletnieks () vt edu wrote:

The rest of us run mail services in the real world, where lots of users buy
laptops, and then actually <gasp, shock> *use* the portability and thus often
end up behind some other ISP's port-25 block.

Why not a VPN solution.  If you have mail servers that your users need,
chances are that you also have file servers, internal web servers.
calender servers, etc.  Should file/web/calender servers all open one
port or internal access and a second port for authenticated external
access?

That might work for corporate networks, but not for hosting providers,
isps, etc.

We have about 10000 domains we manage, a lot of them have active mail
users. Imagine a (low) average of 5 mailboxes per domain. That would
mean my team would have to support 50000 VPN connections? No thank you!

Furthermore, to setup a vpn, you need extra software, there are the
issues when you are behind a NAT (or even double-NAT) etc. Almost all
MUA's support auth-smtp on port 587, and thus this can be used from
anywere (cyber-cafe when you are on holiday, pda's, even some
cellphones, ...).

BTW: Belgium's two biggest isps _do_ block tcp/25 outgoing...


Kind Regards,
Frank Louwers

-- 
Openminds bvba                www.openminds.be
Tweebruggenstraat 16  -  9000 Gent  -  Belgium


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