stop floading http request

since 5 weeks now ,some one is sending 100s of http request per second and caused the shut down of my forum several times.

is there a way to automaticaly stop this type of attacks?
or a php page that can blcok the ip?
any solution ...
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I would recommend requesting from you hosting company to install and configure mod_evasive for this kind of attack.
it will block that ip when it accedes the minimum requests per second.
You're experiencing DOS (Denial Of Service) . This should be stopped by a firewall configured to drop DOS packets.
What's the forum platform? there's code written for PHPBB which blocks spambots registering.. so doing this may help.. as it could block the IP addresses of other miscreants.. assuming you can't get the host to implement DOS protection for you...
I should have mentioned that the DoS attack is *probably* quite low level.. so it's actually stopping your hardware responding, rather than stopping the forum software working, hence the need for DoS firewall hardware service in front of the Forum machine.
Free Tool: Site Down Detector

Helpful to verify reports of your own downtime, or to double check a downed website you are trying to access.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Well I agree with chops_uk , since the firewall helps you with that better than the code,
anyway , take a look at this page:

uk1900Author Commented:
hi guys,
I have vbulletin forum running  in VPS. virtuozzo with plesk
about the  Firewall Setup:
Firewall is not active now. To activate firewall choose one of firewall operation modes.
Select firewall mode
Normal firewall mode
Advanced firewall mode with default policy Accept
Advanced firewall mode with default policy Drop
I'm not sure what the firewall's like..
as you currently have no firewall, you can use either option:
1) activate the firewall and choose default accept .. then implement the DoS prevention
2) activate the firewall and choose default drop.. then open the ports which vbulletin needs (probably 80 for http and maybe ftp).. then then implement the DoS prevention.

2 would be more secure, but more work.. but at least you'd be more secure :)
uk1900Author Commented:

I have no idea how I can implement the DoS prevention!
I clicked on add rule: I got what u see in the: Snippet u can see what
Add Rule   
General Settings 
Policy Accept Drop Reject 
Protocol tcp udp 
Source Address and Netmask  
Source Port or Port Range  
Destination Address and Netmask  
Destination Port or Port Range  
Chain Input Output Forward 
The rule's position in the chain 

Open in new window

uk1900Author Commented:
thank you khaledf,
I will check that
uk1900Author Commented:
any one know how to install mod_evasive ?
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