403 Checker – ARCHIVED

The two websites referenced in this post (astrubal.nawaat.org and censorship.cybversion.org) no longer function and the latter is causing malware warnings in many browsers. All web and download links have been deactivated to avoid errors. We maintain this page only for historical use. Please do not use this documentation for practical purposes.


“403 Access Denied Checker” was developed by the Tunisian blogger and activist Astrubal [http://astrubal.nawaat.org/403-access-denied-checker/]. It is not a circumvention tool. It has been designed to help activists in nations with extensive online censorship to test local blockages.

The software aims to make it easy for any one to quickly check a huge number of URLs and share the result with the public. Its main gaol isn't to help “experts”, but to help get feedback for people with no access to experts, who are living under repressive regimes.

This is an early alpha release, and many things still need to be done to make it more user friendly.


(For download, please see below 4 versions are available, MacOS X, MacOS 8.6-9, Linux, Windows 98/XP )

The procedure is simple and does not require from the user to have administrative rights on the machine that will run “403 Checker”. Any destination folder that the user has write privileges will do.

Just unpack the entire contents of the downloaded archive. That's all, no special installer needed.

Inside 403 Checker folder (Linux version)

Inside the application folder there are several files :
“403 Access Denied Checker.exe“, the program.
ISPs.txt, the file that store the names of local Intenet Service providers.
Url_To_Check.txt, the list that contains the urls to be checked.
Read me file.txt (still empty).
Licence.txt (Who read licences ?)
403 Checker Result folder “” where reports are stored in xml format.

Please keep in mind that Both lists “ISPs.txt” and “Url_To_Check.txt” are widely released with the software for testing purpose. Normaly these lists are intended for Tunisians to check blocked sites (from inside Tunisia).

ISP Popup… can easily be edited (Linux version)

So what to Do ?

For the ISP list, the user doesn't really need it to run the program. But if ever he wants to share publicly his tests the data published won't be accurate. The user should first open the “ISPs.txt” file with any text editor, and add the name of his ISP. It is that easy. And if ever the user decides to share this data, it will be useful for all.

As for the second file, “Url_To_Check.txt“, everyone can insert any data in a tab-separated format : url/SiteName or : url “=>>” SiteName (where “=>>” is the separator).

Both files must be saved in utf-8.

Personnel Data
“403 Access Denied Checker” do not store any personal data of any kind, including IP numbers. The choice has been made not to log IPs. When the user run a test and save the result, only http headers and isp references are stored.

Some codes returned by the program (Win. version)

When checked, each url return whether the “HTTP code response” or an internal code when the server can not be reached due to connection problems. And (for the non experts) it is the 403 code that means very often that the url is blocked for political reasons. However, to get sure the url is indeed blocked, the user can do a right-clic on the the 403 selected row, and choose “show in my browser”. If the browser doesn't also show the page, so there are no more doubt.

“Show in my Browser” (Linux. version)

And the question is: does the url blocked because it points to a private page or for political reasons. Depends in which country you are, the answer is easy (look here for the tunisian scandal of the 403 faked in 404[http://astrubal.nawaat.org/2006/06/12/tunisie-le-scandale-de-la-403-maquillee-en-404/]).

Thanks for all who will take a look at this software. Suggestions and bug reports will be very appreciated.

April 10th, 2007

403 Access Denied Checker For Macos X

403 Access Denied Checker For Window XP/98

403 Access Denied Checker For Linux

403 Access Denied Checker For Macos 8.6/9