Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!clyde.concordia.ca!uunet!tut.cis.ohio-state.edu!ucbvax!hoptoad!tim
From: tim@hoptoad.uucp (Tim Maroney)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Communications Toolbox questions
Message-ID: <9327@hoptoad.uucp>
Date: 18 Dec 89 01:58:33 GMT
References: <9125@hoptoad.uucp> <36869@apple.Apple.COM> <9188@hoptoad.uucp> <37028@apple.Apple.COM> <9223@hoptoad.uucp> <37200@apple.Apple.COM> <1621@intercon.com>
Reply-To: tim@hoptoad.UUCP (Tim Maroney)
Organization: Eclectic Software, San Francisco
Lines: 36

In article <1621@intercon.com> amanda@mermaid.intercon.com (Amanda Walker)
writes:
>The only way I see to write an FTP tool currently is to have the file transfer
>tool talk to MacTCP directly, bypassing the (hypothetical) Telnet tool
>completely.  FTP requires two separate connections, one of which could be
>done with a Telnet connection (the command channel), but one of which is
>most definitely not a terminal-style connection of any sort (the data channel).
>
>Disclaimer: I haven't actually tried writing an FTP transfer tool yet, so
>I may well be just confused.

Nope, you're not confused, you're exactly right.  There's a big
difference between a TCP and a TELNET connection.  IAC characters pass
as data over a TCP connection, while they signal negotiation on a
TELNET connection.  If you tried to use a TELNET connection as an FTP
data channel, you'd have numerous errors associated with every IAC
character in the file.  And if the user side TELNET connection is
set up to do any automatic negotiation, then the whole thing fails.

For the FTP data channel tool to set up its own TCP connection might
work.  Of course, you've got to find out the port of the control
channel to set up the data channel, and there's no way to get this kind
of information from a connection tool. And if the user types a PORT
command, might as well forget about that connection....

>The Comm Toolbox looks like a marvelous effort, but its metaphors seem to
>break down more and more the farther your get from a serial line...

Yes, it looks like it should be called the "Modem Toolbox" as it stands
now.  It simply won't work for LAN functions.  Maybe the solution is
for Apple to hire you and me to bring it up to spec for TCP/IP....
-- 
Tim Maroney, Mac Software Consultant, sun!hoptoad!tim, tim@toad.com

"Philosophy is the talk on a cereal box
 Religion is the smile on a dog" -- Edie Brickell, "What I Am"