[comp.protocols.tcp-ip] FTP implemetation issues

amanda@lts.UUCP (Amanda Walker) (02/04/89)

In our Macintosh TCP/IP product, we face the same issue of exchanging
non-vanilla files between like systems, and so far my preference is to
use "SITE" commands to modify the interpretation of Image mode.  I don't
want to leap into the fray here, that's just how I read the RFC.

Something else that we do with our FTP client is to make it as intelligent
as possible if it can figure out what it's talking to.  Theoretically,
this is pretty easy: just use the SYST command.  Unfortunately, very
few FTP servers seem to implement it, even though it's dead simple to
do.  We get along pretty well by looking at the HINFO fields in DNS
replies, but that doesn't help us differentiate from, say, half a
dozen different VMS FTP servers.

I encourage anyone working on an FTP server to add the SYST command.  I'd
also be interested to know what the responses are from any servers out
there that aleady do implement it.  Just to get things started, here's
what our products return:

	200 MAC-OS TCP/Connect for the Macintosh Version x.x
	200 MS/DOS TCP/Connect for the PC Version x.x

Even if you don't think anyone else cares :-), please at least mail it
to me...

-- 
Amanda Walker			...!uunet!lts!amanda / lts!amanda@uunet.uu.net
			  InterCon, 11732 Bowman Green Drive, Reston, VA 22090
--
"NO one expects the Spanish Inquisition!"

nelson@sun.soe.clarkson.edu (Russ Nelson) (02/04/89)

Speaking of FTP, has anyone implemented RESTart?  Restart requires MODE C
(compressed), which is a simple repeated-byte-packing algorithm.  I
checked radc-tops20's FTP server as well as several flavors of Unix FTP
servers, and none of them support Compressed mode... :-(

Several times I have gotten part of a .5 Megabyte file, and REST would have
been a *real* big help.
--
--russ (nelson@clutx [.bitnet | .clarkson.edu])
"I saved the whales!" - Rebecca L. Nelson, 3.5 years old, on receiving her
Christmas present of a whale "adoption" certificate.  Bless her liberal heart.

braden@VENERA.ISI.EDU (02/05/89)

	
	Speaking of FTP, has anyone implemented RESTart?  Restart requires MODE C
	(compressed), which is a simple repeated-byte-packing algorithm.  I
	checked radc-tops20's FTP server as well as several flavors of Unix FTP
	servers, and none of them support Compressed mode... :-(

Russ,

I am happy to say that this is WRONG!!  All that is required to send
Restart Markers is Block Mode, which is a trivial byte count header shlunked
into the stream whenever the sender feels like it ... eg when it wants to
send a Restart Marker.

Bob Braden
	

nelson@SUN.SOE.CLARKSON.EDU (Russ Nelson) (02/05/89)

I went back to the hosts that I looked at for MODE C to see if MODE B
would work.  They all say "We only support stream mode, sorry".
However, Bob *is* right, I misread the RFC, Compressed or Block mode
will do.

Let me ask the more experienced people on the net: Which do we need first?
Chickens (clients that implement MODE and REST) or Eggs (servers that ...)
I suspect that modifying the freely copyable Berkeley ftp and ftpd would
go a long way to making REST implementation universal.  Is anyone volunteering
or am I volunteering by bringing the issue up?  :-)
-russ

meissner@tiktok.dg.com (Michael Meissner) (02/11/89)

In article <NELSON.89Feb3233605@sun.soe.clarkson.edu> nelson@clutx.clarkson.edu writes:
| Speaking of FTP, has anyone implemented RESTart?  Restart requires MODE C
| (compressed), which is a simple repeated-byte-packing algorithm.  I
| checked radc-tops20's FTP server as well as several flavors of Unix FTP
| servers, and none of them support Compressed mode... :-(

I beleive that Data General's native UNIX (DG/UX) 4.00 FTP does support
RESTart and MODE C operations.  Though of course you probably need
both sides of the connection to support it. :-).
--
Michael Meissner, Data General.
Uucp:	...!mcnc!rti!xyzzy!meissner
Arpa:	meissner@dg-rtp.DG.COM   (or) meissner%dg-rtp.DG.COM@relay.cs.net