Re: Is this mail list dead?

[Crispin Cowan <crispin@wirex.com>]

Luca Berra wrote:

> On Mon, Mar 12, 2001 at 09:07:41PM -0800, Crispin Cowan wrote:
> > How else would you (say) enforce that only the Duly Authorized Mailserver is
> > the one listening to example.com:25 ?  If anyone can bind to port 25, then
> > anyone can kick the authorized mail server over (go find some DoS) and start
> > your own mail server.  Repeat as necessary for various other important
> > services that bind to well-known ports <1024.
> bah, there are a lot of services that start from port>1024 nowadays

No there aren't.  There are a lot of *servants* (peer-to-peer server/client
applications) that use high ports.  True *services* use well-defined ports below
1024, precisely so that they can be authoritative for that host.  If there are
true services using high ports, then they had *better* be using strong crypto
authentication (as was earlier suggested).  For reference, here's the port number
assignments  http://www.isi.edu/in-notes/iana/assignments/port-numbers


> i believe the < 1024 thing was for the benefit of things like
> rlogin/rsh

Where "things like" means "services", then yes :-)

Crispin

--
Crispin Cowan, Ph.D.
Chief Research Scientist, WireX Communications, Inc. http://wirex.com
Free Hardened Linux Distribution:                    http://immunix.org

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