IPP Mail Archive: RE: IPP> Re: Implications of introducing new scheme and po

RE: IPP> Re: Implications of introducing new scheme and po

PETER_E_MELLQUIST@hp-roseville-om3.om.hp.com
Wed, 3 Jun 1998 14:00:13 -0700

If you wish to add security, you may be dealing with up to four ports,
two for HTTP and two more for HTTP-S. Embedded web server
implementations should be able to deal with this fine. The issue
remains reconfiguratoin of Firewalls to allow inbound connections on
all ports. Firewalls can be easily configured, IT folks hate to do it
though.

A beneficial side effect of using special ports for IPP is that of
easy IPP service discovery. Web crawler like tools can easily discover
IPP servers running on say , port 380, and thereby be able to find all
IPP printers within a network. This can allow IPP discovery using
standard tools today. The process would look something like...

For all IP Valid Addresses...
- perform HTTP HEAD request on port 380
- If HEAD response
Add URL to Directory Services List as IPP printer

This same approach has been used by HP OpenView when discovering Web
enabled appliances for management purposes with success on port 280.

The same can be done digging for URI's, it takes more work.

Someone might pursue grabbing port 380 through IANA...

Peter

______________________________ Reply Separator _________________________________
Subject: RE: IPP> Re: Implications of introducing new scheme and po
Author: Non-HP-Peter.Zehler (Peter.Zehler@usa.xerox.com) at
HP-Roseville,mimegw4
Date: 6/1/98 12:52 PM

Scott,
Will your product require no change at all if it is the front end for a
standard web server and an IPP Printer? It seems this would require your
product to listen to 2 ports. An alternative would be to have 2
instantiations, one for regular HTTP and one for IPP over HTTP.
Pete

Peter Zehler
XEROX
Networked Products Business Unit
Email: Peter.Zehler@usa.xerox.com
Voice: (716) 265-8755
FAX: (716) 265-8792
US Mail: Peter Zehler
Xerox Corp.
800 Phillips Rd.
M/S 111-02J
Webster NY, 14580-9701


-----Original Message-----
From: Scott Lawrence [SMTP:lawrence@agranat.com]
Sent: Monday, June 01, 1998 3:02 PM
To: ipp@pwg.org
Subject: IPP> Re: Implications of introducing new scheme and
port for existing HTTP servers


On Mon, 1 Jun 1998, Carl-Uno Manros wrote:

> 1) the introduction of a new scheme called "ipp"
> 2) the introduction a new default port number for IPP servers.
>
> Before the IPP WG responds to those suggestions, the IPP WG would
like to
> get some advice from the HTTP WG on the implications of such a
change.
> In particular, we want some feedback on how easy or difficult it
would be
> to configure existing web servers to accomodate the suggested
changes.

Answering for EmWeb, our embedded web server:

The new scheme (1) would require a very minor change from our
existing
product, which requires that he scheme be 'http' if it is present at
all. We'd need to allow 'ipp', and perhaps add a check to ensure
that
it is being used on the proper port (if that is deemed to be
important).
If the client does not send the scheme, then there would be no
change.

The new port (2) would be no change at all, since it can already
operate on any port. One might wish to recognize that the default
port
for an 'ipp:' scheme redirect would be different than for an 'http:'
redirect, but that's a very minor matter.