Saturday, 19 July 2014

Check your Public IP address Geo Location using the command line on Linux

If you are using VPN connections it can be important and useful to be able to check your current public IP. For me going to one of the many web sites that offer such a service is slow. As always on Linux the command line is the fastest way. Searching around I found geoiplookup which did exactly what I wanted. It uses the GeoIP library and database to find the Country that an IP address or hostname originates from.


$ geoiplookup

Displays the country that originates from e.g.

NL, Netherlands

You can have a simple bash script like :

echo "Current Public IP is :"
curl -s | sed 's/.*IP Address: \([0-9\.]*\).*/\1/g'
sleep 1
PUBLICIP=$(curl -s | sed 's/.*IP Address: \([0-9\.]*\).*/\1/g')
geoiplookup $PUBLICIP

To install on Arch :

$ sudo pacman -S geoip

To install on Ubuntu, Linux Mint or Debian

$ sudo apt-get install geoip-bin

By default the IP to country database is located at /usr/share/GeoIP/GeoIP.dat

Monday, 14 July 2014

How to stop embedded images tracking your location on Gmail

You may think that the only way people can tell if you opened an email is the good old 'read receipt' but there is another more subtle method. That method is by using embedded images to track individuals. Currently this method is used by phishers, marketers and spammers to track where people open emails and to track other useful information.

The most common method used for email tracking is embedded images. The process is relatively simple :

- Email is created in HTML

- Included is a reference on a remote server that the sender owns or has access to

- Each email can be given a unique URL to track what individual opens emails

- Contained within the HTTP request from your email client to obtain the referenced image will be your IP address (which can track your location unless you are on a VPN) to at least to your city, your browser and Operating System.

All very useful information that can be used to draw a number of conclusions about the reader :

- Where was the email opened

- What time was the email opened

- How long from when the email was sent was it opened

- What type of device was the email opened on

- Prove that it made it past any spam filters in place

- Show that the email is valid and in active use

Gmail Solution

With Gmail like most privacy features from Google you must opt-out which can be done as follows :

Browser Client

- Select Gear icon then Settings

- Under the General tab look for Images (Fourth down currently in the list)

- Select 'Ask before displaying external images'

- Scroll to bottom of screen

- Select Save Changes


- Within the Gmail App on Android

- Select menu on left and scroll down to the bottom (may take a while if you have lots of labels) until you see Settings   

- Select each email address in turn (if your have multiple) and scroll to bottom and select Images

- Change to Ask before showing

Sunday, 6 July 2014

OpenWRT : Use Google Public DNS

By default you will be using the DNS servers supplied by the ISP you subscribe with. With OpenWRT its easy to change the DNS service that you use to an alternative option. A popular option is the Google Public DNS service.

Advantages of using Google's DNS are :

  • Faster web browsing
  • Improved security
  • No redirection
Note - depending on your location it could be slower. Your geographic location will determine the closest Google DNS server you will be directed to.

In OpenWRT to change is a simple process

  • Open Luci web interface
  • Select 'Network' -> 'DHCP and DNS'
  • Locate 'DNS forwardings'
  • Enter ''
  • Press '+' button to enable a second entry
  • Enter ''
  • Select 'Save & Apply'
It should look similar to the following :