Use case - Finding proxy that allows to post on craigslist.org.

Quite often I get asked how to find proxy servers that allow to post on craigslist. The issue that particular site has blacklisted most of the public proxy servers. Which ordinarily could be solved by adding user test target as described here. But that's not quite enough - issue is that craigslist will do multiple redirects before telling you that you are allowed to post or not.

Configuring Test Target for Craigslist

First of all I opened up http://post.craigslist.org/ and waited it to redirect me around. Then picked a string I would use as a validation of correctness - "please limit each posting to a single area and category". After which checked both "accept redirected pages as valid" and "Follow redirects".

Which means that program will follow all the redirects and then check if the last landing page is valid. Now run the test by clicking "Re-Test" button, if all is fine target in the tree will light up as green.

 After all this is done you can disable other targets and leave only craigslist on. Next time when you scan proxy servers only ones that work with craigslist will be marked as working ones.

Other Sites

Applying this technique to other sites is possible. However there are limitations. If there are captchas or javascript redirects - it will not work. As support of such would require a full web browser implementation.