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Wanna see a demo of an FtpServer - the Ftp analogue of an Atapi device - mixing up the 
bytes of one command with the next?

Over Christmas I dug into Ftp a little.  Fun to see a new slant there on all the same 
storage interface issues that we have here.

At a Windows Ms-Dos prompt, try the following.  [[[This works for me at home as shown, 
but here at work our firewall proxies Ftp traffic in a way that breaks this demo.]]]

[[[Everthing after a > or a : you have to type yourself.]]]

C:\> ftp

ftp> debug
Debugging On .

ftp> open members.aol.com
User (members.aol.com:(none)): anonymous
---> USER anonymous
331 Password required for destination user 'anonymous'.
Password:
---> PASS [EMAIL PROTECTED] 
... [if you die via reply 421, 530, whatever, then retry this much until finally you 
do get thru] ...
...
230 Guest login ok, access restrictions apply.

ftp> quote noop
---> noop
200 NOOP command successful.

ftp> quote noop abc
---> noop abc
500 'NOOP abc': command not understood.

ftp> quote quit
---> quit
500 'NOOP abc': command not understood.

ftp> quote quit
---> quit
221 Goodbye.
Connection closed by remote host.

[[[news:comp.protocols.tcp-ip credibly suggests the appearance here of mixing one 
command with the next arises only because the FtpServer here chose to reply twice to 
the "quote noop abc" ... analogous to when an Ide device is rude enough to raise INTRQ 
some time after a host polled x3F6 AlternateStatus and saw BSY = 0.]]]

[[[ftp.microsoft.com is as easily confused as members.aol.com, but to see this you 
have to find an ftp client that will let you open a connection without automagically 
supplying a user name and password.  Then you can see the FtpServer there will 
catenate the "abor" of one "quote abor" command with the next if you send your "quote 
abor" before a user name.  What's fun is if you do this more than 127 times: then you 
blow out the command input buffer there.]]]

Happy Thursday.    Pat LaVarre


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