Firewalls prevent unauthorised data being transferred from and to your computer. This effects data between applications connecting websites. Usually firewall users can "allow" permitted applications to transfer data and set various levels of security.

For example, F3.org.uk uses the HTTP_REFERRER information to check if you're logged into the website. Some firewalls (most notably software firewalls such as Norton and ZoneAlarm) block this information being sent to the server by default. This could prevent you from logging into the F3 web site. Typically this becomes evident when you log into the website, the login is confirmed, and you still see the 'login' box on the page, and you're not actually logged in at all.

The solution is to add www.F3.org.uk into to the Trusted Sites list of your firewall application and also your browser (using Trusted Zones etc).

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Zone Alarm Pro:

1. Click Privacy
2. Click Cookie Control
3. Click Custom
4. Uncheck "remove private header information"
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Windows XP's Internal Firewall

1. Open XP's Control Panel
2. Double-click Networking and Internet Connections
3. Select Network Connections
4. Right-click on the connection to disable, then select Properties
5. On the Advanced tab, clear the Protect my computer or network checkbox
6. Press OK
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Norton Internet Security 2002 (or earlier)

1. Open NIS or NPF.
2. Click Options.
3. Click Internet Security or Personal Firewall. (This step is not always needed.) The Options window appears.
4. Click Advanced Options.
5. Click the Web tab.
6. Click Add Site. A new site/domain box appears.
7. Enter www.f3.org.uk and click OK. The site name now appears in the left frame of the Advanced Options window.
8. Click the name of the new site.
9. Click the Privacy tab.
10. Check the "Use these rules for..." box.
11. Change the Referrer from "Block" to "Permit."
12. Click Apply, and then click OK.
13. Click OK to close the Options window.
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Norton Internet Security 2003/2004

1. Open NIS or NPF.
2. Do one of the following.
* In NIS/NPF 2003, click Options > Internet Security or Personal Firewall (This step is not always needed), and then click the Web Content tab.
* In NIS/NPF 2004, double-click Privacy Control, and then click Advanced.
3. Click Add Site. A new site/domain box appears.
4. Enter www.f3.org.uk and click OK. The site name now appears in the left frame of the Options window.
5. Click the name of the new site.
6. Click the Global Settings tab.
7. In the "Information about visited sites" section, clear "Use default settings."
8. Click Permit.
9. Click OK to close the Options window.
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Norton Internet Security 2005

1) Privacy Control
2) Click on Configure
3) Choose 'Custom Level'
4) Uncheck 'Browser Privacy'
5) Click 'OK'.


Techincal Information about HTTP_REFERER's (for those of us who do actually care!!)

When you click a Web page, your browser notes the current page that you are on and sends that information to the server of the new Web page. This way, the server for the new Web page knows the last Web page that you viewed.

For example, if you are on www.symantec.com and click www.microsoft.com , the browser sends www.microsoft.com the information that you are currently viewing www.symantec.com. If you block referrer information, the server of the page you are requesting to see does not know what page you saw last. By default, Norton Internet Security (NIS) and Norton Personal Firewall (NPF) block this information. Some Web sites require this information before they allow you to see their pages.

The reason for this (with F3's site at least) is lets say your logged in and browsing a page of the members area. Then you go and have your lunch with a pint and arrive back at work an hour later. During that hour, your session may have expired and you've been logged out (from the server end) but your still seeing the last page you accessed. If you then click on a button which you need to be logged in to access, you get shown the login page. When you successfully log in, your taken back to the page you tried to get to before, but logged in this time with the appropriate permissions. Without HTTP Refferal this would not be possible and you'd just be directed to the home page or something.