Lojic Technologies

Posts Tagged ‘network

Ubuntu Linux 8.04 – Wake on LAN

with 3 comments

Now that I’ve switched to a Macbook Pro with OSX Leopard as my primary desktop, I’ve located my Ubuntu machine in another part of the house to be accessible to my children. Not wanting to walk to the room where it’s located just to flip the power switch, I researched how to get “wake on LAN” working, so I could power it up remotely.

1. Enable the appropriate setting in your BIOS. Mine had something to do with wake on PCI device.

2. Install ethtool if you don’t already have it.

sudo apt-get install ethtool
cd /etc/init.d
sudo vim wakeonlanconfig

Add the following lines to that file:

#!/bin/bash
ethtool -s eth0 wol g

Install the script:

sudo update-rc.d -f wakeonlanconfig defaults

Run the script:

sudo /etc/init.d/wakeonlanconfig

3. Keep the network interface alive after shut down.

sudo vim /etc/init.d/halt

Change the following line:

halt -d -f -i $poweroff $hddown

to the following line (i.e. remove the -i)

halt -d -f $poweroff $hddown

4. Get the MAC address

ifconfig | grep HW

5. Send the magic packet via the following Ruby program:

require 'socket'
mac_addr = "x21x53x39xB3x90x42"
s = UDPSocket.new
s.setsockopt(Socket::SOL_SOCKET, Socket::SO_BROADCAST, 1)
s.send("xff"*6 + mac_addr*16, Socket::SO_BROADCAST, '10.0.0.255', 7)

Written by Brian Adkins

September 3, 2008 at 12:23 am

Surf Securely Using SSH

with one comment

This is so easy, you’re gonna love it! Thanks Tyler Pedersen.

Motivation

I’ve been using my laptop more frequently at wifi hotspots. Many web sites I visit encrypt traffic with SSL for authentication, but after that they send traffic in the clear which means the cookies that are used for authentication purposes are sent in the clear, so anyone with a sniffer within range of my laptop could easily intercept the traffic, steal my cookies and impersonate me on the web site. Not good! So, I went looking for a simple solution, and found a great article about using ssh for this purpose. Ya gotta love open source software 🙂

Prerequisites

I’ll assume the following:

  1. You’ve used ssh before
  2. You have access to a remote host running sshd

How To

Issue the following command on your local computer:

ssh -Nf username@hostname.com -D 1080

replace username@hostname.com with the appropriate information. Look at the man page for ssh, or read the article linked above for an explanation of the options.

The next step is to configure Firefox to use the SOCKS proxy you setup with the above command. I’m using Firefox 2.0.0.6 on Ubuntu 7.04 Linux.

Edit | Preferences | Advanced | Settings

Pulls up the following dialog:

socks.png

Notice how I’ve switched from “Direct connection to the Internet” to “Manual proxy configuration”. I’ve also set the SOCKS Host to be ‘localhost’ and the port to be ‘1080’.

I can now surf and have encrypted traffic between my local computer and the remote host I ssh’d to. The traffic between my remote host and the destination web site will be unencrypted, but hopefully that traffic is harder to sniff without being detected.

At this point, I tested it out and everything worked fine. I then killed my local ssh process and Firefox complained about the connection being reset, so I knew it was in fact sending data over the ssh tunnel.

The final step is optional, but if you want to avoid having the bad guys detect your DNS requests (or possibly redirect them – d’oh!), you can configure Firefox to route DNS requests through the proxy.

  1. Type about:config in the Firefox address bar.
  2. Look for network.proxy.socks_remote_dns and set the value to true

Is that easy or what? Thanks again Tyler.

Written by Brian Adkins

August 2, 2007 at 12:28 am

Posted in internet

Tagged with , , ,