[lug] 3 Questions: 1) Port Forwarding 2) Unison 3) Job Management Software 4) Test Apache

[Daniel Webb]

On Mon, Feb 14, 2005 at 01:17:28PM -0500, Gordon Golding wrote:

> 1)  Port Forwarding
> 
> >>>>>>>>On Fri, 21 Jan 2005, Daniel Webb wrote:
> > Did you realize you can run servers on a machine behind a firewall with
>  a single SSH command, changing nothing on the firewall?  ...  I have written a small script to keep a tunnel up all the time as well if anyone has a use for it.
> 
> Does anyone have Daniel's email address?  I want to get that script,
> so I can automate backups from remote locations (non-addressable or
> behind Firewalls) to a central Backup Server.

I finished up the script I was working on:

http://www.danielwebb.us/software/ssh-reverse-tunnel/

For the reverse port-forwarding case (the case where you are forwarding
from a machine you normally don't have access to without the
reverse-forwarded port), it's more complicated than just a simple shell
loop, and my script solves that problem.  The other solution is a
package called autossh, but I have found it to fail under the tough
conditions I'm dealing with, while my script will keep the connection up
(or more precisely, stubbornly keep recreating the connection once it
fails).  For simpler conditions I recommend autossh, since it's easier
to start using (just replace "ssh" with "autossh" basically).

I also added the capability for a PPP VPN over SSH in the script for the
same conditions described above.  It's not the ideal way to create a
VPN, it's slow and kludgy, but it actually works fairly well, and the
setup is very low, and you don't have to have any ports open except the
ssh port.

This allows me to admin my sister's computer, which is behind a wireless
NAT firewall that she doesn't have control of (or even know where it is,
actually).  I don't know of any other Free software other than my script
to accomplish this in a robust way.

Anyone who's interested please give me feedback, since this is my first
public release.  I'm shooting for the level of code and documentation
quality seen in the GNU project packages.