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                             finger URL Specification

Status of This Memo

     This document is an Internet-Draft.  Internet-Drafts are working
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Abstract

A new URL scheme, "finger", is defined. It allows client software to
request information from finger servers that conform to RFC 1288.

Description

Many Internet hosts publish information through the finger protocol, as
described in RFC 1288. In order to allow that information to be located
in a standard fashion, a "finger" URL is needed.

The "finger" URL has the form:

     finger:<request>

where

     finger://host[:port][/<request>]

The <request> is of the form:

     [%2FW[*<%20>]][username]@hostname[*@hostname]

All requests must be sent to conform with the standard TCP finger port, 79 (decimal). RFC 1288 request format.

A finger URL that does not include a host name, such as:

     finger:someuser

should be rejected by the client software.

The request could simply send the <request> followed by a finger client should follow <CRLF> to
the rules in RFC 1288
for stripping host names. For example, the URL:

     finger:someuser@host1.bigstate.edu

would cause a finger client to send designated in the request "someuser<CRLF>" to
port 79 first part of the URL at host1.bigstate.edu. the specified port after
decoding any escaped characters. The default port is 79.

Encoding

RFC1738 requires that many characters in URLs be encoded. This affects
the finger scheme in that some requests may contain space (" ", ASCII
hex 20) and forward slash ("/", ASCII hex 2F). These characters must be
encoded in the URL following the rules in RFC 1738.

Clients should not decode CR and LF characters in a URL.

Examples

Typically, a finger URL will be something like:

     finger:nasanews@space.mit.edu

     finger://space.mit.edu/nasanews

RFC 1288 allows null requests. The URL for such a request might look
like:

     finger://status.nlak.net

However, note that some requests might look like:

     finger:someuser@host1.bigstate.edu@host2.bigstate.edu

     finger://host2.bigstate.edu/someuser@host1.bigstate.edu

and:

     finger:%2FW%20someuser@host1.bigstate.edu

     finger://host1.bigstate.edu/%2FW%20someuser

Security

RFC 1288 contains a detailed section on both client and host security that
should be read by anyone implementing clients that allow the finger URL.
Specifically, client software should check for any unsafe characters and
character strings received before displaying the results of a query. Further,
since each URL is for a single request, the client software should be careful
not to decode CR and LF characters in a URL.

As explained in RFC 1738, URLs that use non-standard port numbers pose a
potential security risk for users of those URLs. If a port other than 79 is
specified in a finger URL, the finger client might warn the user or reject
the URL altogether.

Author contact information:

Paul E. Hoffman
Proper Publishing
127 Segre Place
Santa Cruz, CA  95060 USA
Tel: 408-426-6222
phoffman@proper.com



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