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Re: Yet another thread on the legality of port scanning
From: Charley Hamilton <chamilto () uci edu>
Date: Thu, 18 Mar 2004 09:32:58 -0800

On 2004-03-17 Charley Hamilton wrote:
Authorized users are told they are authorized users.  If you are not
an authorized user, what difference does it make what protocols are

Then how do I become an authorized user of www.google.com?


See the reasonable man hypothesis comments below.  Reasonably, if someone
names a server www.foo.bar, most people would conclude it is intended
to be accessible to the general public. The fact that an individual has advanced techincal knowledge does not authorize them to employ that knowledge
to identify otherwise unannounced services.  Knowledge = power, not

The "reasonable man" hypothesis applies to connecting to a system to
which authorization is in doubt.  Would a reasonable man conclude that
http://www.cnn.com is an acceptable connection in the absence of
explicit permission?  I would say yes, he would. Would a reasonable
man conclude that ftp://www.cnn.com is an acceptable connection in the
absence of explicit permission? I would argue no, he would not.
What's the difference?  HTTP is generally accepted to be a public
connection, in the sense that it is intended as a shared resource, to
be accessible to all.  FTP is not generally accepted as such,
regardless of what electronic storefront happens to be offering the

That's simply not true.

I admit FTP was a poor choice.  Detailed response in reply to
Barry Fitzgerald.  Were you also referring to something else?  The terse
answers don't make for much of a conversation.  More like you're
delivering divine wisdom.

Similarly, www.foo.com is generally expected to be a public http
server.  Therefore, making an HTTP connection to that server is
reasonable.  accounts-payable.foo.com is *not* generally expected to
be a public http server.  Therefore, it is not reasonable to assume
that it would be offering public http services.  Any such services
would reasonably be intended for authorized users only.


That's a one word answer if I ever saw one.  Why no?  Why is this not
the reasonable conclusion?

Ansgar Wiechers


Charles Hamilton, PhD EIT               Faculty Fellow
Department of Civil and                 Phone: 949.824.3752
    Environmental Engineering           FAX:   949.824.2117
University of California, Irvine        Email: chamilto () uci edu

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