I want my linux (ubuntu 14.04 , 64 bit) system device which has a 3g card in it to have restricted access of internet . I want to build a scenario where if the card is active, the system should be able to connect to any url with the pattern mysite.com and google.com . Incoming connection won't be a problem. If web address can not be filtered even IP address can also be used .

Is Iptables the answer for it ? . How would we use IP tables to add the rules that will allow traffic only to two sites and not others. I want to do this procedure again and again (like after inserting or removing the card ) . How can I achieve the desired result ?

  • Do you have another source of Internet connectivity other then the card?
    – davidgo
    Jan 29, 2016 at 4:59
  • Yes , the lan port and wifi card are there but looking 3g card as the primary source of internet Jan 30, 2016 at 13:30

1 Answer 1


Yes, iptalbes is the answer for the filtering part.

To enable some rules when inserting the device, depending on the distribution, you can take a look at udev which handles, amongst other things, device naming and USB insert for example and make it execute a specific script.

As you are running Ubuntu, a simpler way would be to take a look at /etc/network/interfaces. The 3g card would have a fixed interface name (thanks to udev), so in the interfaces file, you can specify a/some pre-up or post-up scripts for this interface that will apply your iptables config "on the fly".

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