Hi all,
Could any one tell me how can I filter, the inbound URLs of our server. I mean the URL requests sent by the people trying to access our server. How can I use firewalls for that?

thanks and regards,
-anu

There are a number of different ways of doing this. With the firewall you can use iptables string matching to match certain URLs and then reject those packets, however Apache's mod_rewrite module is a much better way to do anykind of URL filtering or modification. There is a good guide to using it in the www.apache.org documentation.

Thanks Boss,
But I want to reject all the URLs which are not on my webserver... Or in other words, URls which my web server can't hold... Or is there any possibility, by which I can maintain a database of my web server's urls and when a user requests a page... My server checks against the database... If found legal then only, it feeds the user request...
Thanks n regards,
ANU

Using iptables probably is not a good way of doing it then. An application level firewall/proxy like Zorp or even squid might work better. Mod_rewrite has a -U option that can be used for matching URLs that don't exist, however it can use alot of resources in doing that (it makes an internal query of the URL). I don't see why the standard HTTP 404 status code isn't ok? It might be a bit more clear if you explain what you are trying to do (or prevent). For example if you are trying to block malicious HTTP requests, then something like mod_security may be more appropriate.

Thanks Boss,
I was also thinking of modsecurity... Just got confirmation from you... Thanks once again...

Regards,
ANU