[svlug] Consider my mini-HOWTO

Bill Jonas bill at billjonas.com
Sun Mar 18 00:42:02 PST 2001

On Sat, Mar 17, 2001 at 11:59:58AM -0800, Rick Moen wrote:
> <shrug>  It works, and speed seems basically bottlenecked by the
> transport.  Which reminds me:  I like your suggestion of netcat, very
> much.  The extra trouble of starting piped processes on both ends might
> be warranted.

A friend of mine once suggested:
Sender: tar cvpf - <dir> | gzip -c | nc -v -v -w 2 remotehost port
Receiver: nc -v -v -l -p port | gunzip -c | tar xvpf -

(I forget how similar this is to what was posted on the list earlier.)  Of
course, the gzip can be omitted.  You'd probably want to over GigE,
possibly 100BaseTX.

BTW, how secure is this from a data integrity standpoint?  I've only done
this a couple of times (and only on my own switched mini-network at home;
I wasn't talking about doing this over the *Internet*, for God's sake),
and each time, I've ipchained the port I was using to only accept from the
other host.  Would it be possible from a third party to insert bogus data
in there?  Easily?  The more I think about it, the more it seems it'd
require packet forgery, but I've forgotten a couple details of TCP and how
daemons work.

Oh yeah, and it's a great method to use if you don't have room on the
sending machine to create a temporary tarball.  :)

Bill Jonas                | "In contrast to the What You See Is What You
bill at billjonas.com        |  Get (WYSIWYG) philosophy, UNIX is the You
http://www.billjonas.com/ |  Asked For It, You Got It operating system."
http://www.debian.org/    |  --Scott Lee, as quoted by Lamb and Robbins

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