Automatically modify iptables based on Apache log data to block badly behaved clients

Question

Is there any tool on Linux to automatically modify iptables so as to block a troublesome client based on an analysis of the Apache log? I help run a site that sometimes get overwhelmed by requests from a particular user. The only solution is to add an entry in iptables to block the offending client. Its usually too late by the time I can react manually - hence, I would like some rule based mechanism to modify the iptables. I would guess that some kind of fuzzly logic or statistical analysis would be necessary.

Answer 1

You can use something like fail2ban, which IIRC, has an Apache log checker built in.

Answer 2

You might want to consider using iptables to rate-limit incoming connections. Which in its most basic setting will give you the ability to limit incoming connections to a number per minute.

For example, you might want to only allow 10 pings per minute from a single IP address. It does get a little more sophisticated than that, with the option to set burst limits on top of long term average limits.

Some good instructions on setting it up http://kevin.vanzonneveld.net/techblog/article/block_brute_force_attacks_with_iptables/

Answer 3

Check out OSSEC. Best log file analyzer I've used. It also supports active response based on analysis.