Disabling Referer Headers in Firefox

Given the awesome work detailed by Bala from AT&T, and some recent privacy related measures I have been taking in my Firefox browser (see https-everywhere and adblocking fb), I have decided to instruct my browser to stop sending the Referrer Header (nb: incorrectly referred to as the ‘referer header’), when I am clicking around on the web.

The following example shows the Referrer header of the HTTP request telling facebook.com, that I have just been looking at a page about HIV on the NHS choices website.

GET /<br /> Host: www.facebook.com<br /> User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_6_4; en-gb) AppleWebKit/533.18.1 (KHTML, like Gecko) Version/5.0.2 Safari/533.18.5<br /> Accept: application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5
Referer: http://www.nhs.uk/conditions/HIV/Pages/Introduction.aspx
Accept-Language: en-gb<br /> Accept-Encoding: gzip, deflate<br /> Cookie: presence=DJ290173073BchADhA_22112.channelH1L60X...

I followed instructions on the following blog post http://cafe.elharo.com/privacy/privacy-tip-3-block-referer-headers-in-firefox/ to configure my Firefox instance to not send the “referer header”.

In short, the steps needed are as follows:

  • Type about:config into your firefox awesome bar, to bring up your settings
  • find the setting network.http.sendRefererHeader. This is probably set to 2.
  • Choose one of the following values:
    • 0: Completely disables the referer header (mischa’s setting)
    • 1: Sends a referer header when following a link to another page, but not when loading images on the page
    • 2: Always sends the referer header (default)

I am going to experiment with setting it to 0, disabling the referer header all the time, I will post back here to say if it causes me any problems.