Norton Internet Security – Issues with Firewall Protection – problems with showing pictures and wordpress etc.

I’ve been having a few problems with a couple of my own Internet sites when accessing them from my desktop PC. The sites were working fine on my laptop, so I thought the problem was with the setup of the Firefox browser on my desktop PC. It turns out the problems are actually due to Norton Internet Security.

The first issue I fixed a while ago, which was that some of the images were missing on a couple of pages. I tracked it down to a problem with the Ad-Blocking feature of the personal firewall in the Norton Internet Security Suite. As a result I have already posted Ad blockers – Friend or Foe? This is therefore the first feature that I have turned off. Firefox (and indeed Internet Explorer) already include a pop-up ad blocking feature, which are the ads I really want blocking.

The latest issue was a bit harder to identify. I use wordpress for creating my blog entries. When editing there is a "Save and Continue Editing" button that allows me to save what I’m typing as I go along. This then reloads the page so that I can continue editing. On my desktop PC this did not reload the page, but left me on a blank page.

With a bit of digging around I found that this was most likely due to the http referrer not being sent. For those not used to techno-gabble, whenever you go to a website by clicking on a link, it not only tells the server what you are wanting to get, but also where you have come from. As a webmaster this is very useful, as you can see how many of your visitors come from certain search engines, or that have come from specific sites. WordPress uses this value as a (very basic) security feature to ensure that you are coming from that site.
I checked the config of firefox for the Network.http.sendRefererHeader entry, which was set correctly. As it still wasn’t working, and as I wanted to upgrade to the latest version of the browser anyway, I completely removed firefox, including my profile and then reinstalled it. This still didn’t fix the problem. It was after this that I thought maybe there was something else on the computer blocking it, and remembering my problems with the ad-blocker I checked Norton Internet Security. Lo and behold there is a feature called Privacy Control, which was blocking the http referrer value as well as other things such as the browser name etc. I’ve now turned this feature off and it has fixed the problem.

Both these parameters are set to their medium levels by default. Unless you are really paranoid I suggest that you turn off both:

• Ad-Blocking
• Privicy Control