Thank you for the reply. I have actually just signed up and did nothing more as I have no idea about the rest. We are on a dedicated server for our website and I have root access to WHM. Our web site is under attack at the moment. Hosting provider did a qucik workaround adding this code to Wordpress index.php:
exit('<a href="">Giris icin tiklayiniz</a>');
I really need your help as this is not a logical solution for long term. I choose this hosting company as it was a gold LSWS partner and we have 2 CPU LSWS license. I can provide login info if you can help.
As the above link explains, SYN floods attack the server at the TCP level and thus an HTTP server (like LSWS) isn't going to be able to do much about them. The proxy service should be able to stop it, but the proxy service is a free service. If that doesn't perform to your expectations, you might need to look into other paid services.
Well, the first thing I would suggest is to harden your kernel (see the blog post I referenced above).
That, though, is not meant to block big SYN floods. If that hardening doesn't stop the flood (and I suspect it might not), you'll have to look to another option:
1. Rent a hardware firewall
2. Have someone knowledgeable set up a proxy service like CloudFlare (it must be someone knowledgeable)
3. Talk to your host about blocking it at the network edge (you may have to pay more for this help)
I don't doubt that you're with a good host, but not all hosts specialize in DDoS protection. You may need to pay extra to your current host to get more help (or rent hardware) or find someone who can help you set things up (or switch to a host that specializes in DDoS protection). Either way, our Anti-DDoS Proxy service isn't right for you and changing settings in LSWS isn't going to affect things.
The last option, of course, is just to wait for the attack to end. I assume that's not an option, though.