This "argument" between Carl and Peter is a rare, great pleasure, where
the participants are both knowledgeable and rational and clear enough
that it's easy to follow and appreciate and even learn from their
arguments.
Thanks guys!
--Paul Gloger
------------------------------------
From: kugler at us.ibm.com
To: "Zehler, Peter" <Peter.Zehler at usa.xerox.com>
cc: jkm at underscore.com, ipp at pwg.org
Date: Fri, 11 Aug 2000 10:56:47 -0600
Subject: RE: IPP> notification methods
Peter-
I once tried to run a server on an ATT Worldnet dial-up account. It just
didn't work. Their T&Cs say
Additional Rules of Member Conduct
1. not use your AT&T WorldNet Service dial-up connection to host a
dedicated Internet server site.
It's easy enough for them to prevent you from running a server, simply by
blocking incoming connections. Whether or not they were actually blocking
me, or something else was wrong, I don't know. Anyway, there are likely to
be other problems. For example, (from the DSL Reports knowledge base,
http://www.dsl-reports.com/information/kb/):
private ip
Some DSL (or cable) networks may provide you a private IP address. The
good news is that probably doesn't change, and is secure. The bad news is
that it isn't a real IP so nobody on the internet can reach you, although
you can reach everyone. This is essentially NAT implemented by the
provider on a grand scale.
NAT
NAT stands for Network Address Translation. NAT is a technique for
translating one set of IP addresses, often private, to another set, often
public. Compare NAT to socks -- NAT is often implemented on a router or
specialized NAT box, although it is equally commonly implemented on a PC,
running NAT software.
NAT is a very flexible technique, but in the DSL world you will
interested (or maybe using) just one implementation: NAT setup to allow a
single public IP address to be simultaneously reused by multiple internal
PCs with private IP addresses. To the outside world, you appear to have
only a single IP, but you actually have many devices 'behind' this IP
address.
Note, you don't get something for nothing here! With NAT, as with socks,
incoming connections can be problematic to setup, requiring configuration
on your NAT capable router, or NAT software, to assign (map) external
services (web, FTP and so on) through to specific internal machines. Many
NAT capable devices or software are not sufficiently flexible to cope
with all requirements and software you may have, and some 'NAT
unfriendly' protocols break, even if NAT maps them correctly!
Certainly you can get multiple fixed IP addresses, etc., if you're willing
to pay for it. The question is: is the marginal utility of INDP
notifications sufficient to justify the cost of these services.
-Carl
"Zehler, Peter" <Peter.Zehler at usa.xerox.com> on 08/11/2000 10:01:30 AM
To: Carl Kugler/Boulder/IBM at IBMUS, jkm at underscore.com
cc: ipp at pwg.org
Subject: RE: IPP> notification methods
Carl,
I don't know who your ISP is but mine has no control over a server running
on my host. They do control the length of my IP lease. In my case the
lease lasts hours. Certainly enough time for a notification. (Not enough
time to host a business...they charge for that.)
I can have a fixed IP address and I can have multiple IP addresses if I so
desire. The use of INDP assumes programmatic interactions in near real
time. If I build an application that relies on this it may well impose
requirements on system/network configurations as well as influence the
components I buy.
I see a real need for programmatic as well as end user notification. We
should be specifying and building enabling technologies. Our role should
be
enable policy not to enforce it.
Pete
Peter Zehler
XEROX
Xerox Architecture Center
Email: Peter.Zehler at usa.xerox.com
Voice: (716) 265-8755
FAX: (716) 265-8792
US Mail: Peter Zehler
Xerox Corp.
800 Phillips Rd.
M/S 139-05A
Webster NY, 14580-9701
....