Piece of Unix Hints

You may want to establish a full IP connection to a remote host (or remote lan) but you may not have any VPN software on the remote host, or on your host.
There is a solution using SSH and PPP with the command

pppd pty 'ssh -x -t -e none user@server /usr/sbin/pppd passive noauth 9600' noauth 10.0.0.1:10.0.0.2

You have to use key authentication because the tty is redirected to pppd so you can’t be prompted for a password.
With this command, you can reach server at IP 10.0.0.1.
By playing with pppd and route tables you can extend the IP tunnel to the entire remote LAN.

This has been tested between Mac OS X and NetBSD but should work with any system.
It works but it’s very slow.

On some system you may have TTY problem, if it’s your case take a look to http://shinythings.com/pty-redir/ or http://www.ishiboo.com/~nirva/Projects/vpn/

Why using SSH to transfer data when you can use SCP/SFTP ?
Because sometime SCP is disable in SSH configuration.

So here is an easy way to transfert data with ssh. Run something like this

ssh -C <host> "cd /path/to/folder/to/transfer; tar cvf - *" | tar xfv

-C will compress tranfer using gzip, I didn’t do any test to see if it’s better to use -C to compress on the SSH level or to use tar cvzf to compress the tar file. If you do please give me result !
“| tar xvf” will extract file in your current directory, of course, you may want to leave them in the .tar file.