Server Fault is a question and answer site for system and network administrators. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

This question already has an answer here:

My VPS is suffering from a (D)DoS doing a SYN flood with spoofed IPs. I'm right now searching from ways how to be able to defend (at least a bit) against it. It's running a DirectAdmin apache2 webserver. Mainly used for serving PHP and MySQL.

We are using CloudFlare, which are saying that they are able to mitigate (D)DoS at some level, now the attacker knows our real IP address, so CloudFlare isn't helping a bit.

I've done some searching on the net and found out about enabling SYN cookies, to defend against it. I've checked my settings and it seems it was enabled all along.

I've also read about that Varnish is able to defend against SYN flooding and Slowloris attacks, now I'm pretty interested in using that.

The thing is that CloudFlare is already caching a lot from us, and I don't wish to spend too much resources on Varnish. Is it possible and smart to set up Varnish only for the better handling of requests? Are there perhaps better ways which I've missed?

Thanks in advance, Martin

share|improve this question

marked as duplicate by Tom O'Connor Aug 25 '13 at 21:25

This question was marked as an exact duplicate of an existing question.

I'd request a new ip address (changing the ip address) from the VPS provider. That would be the simplest solution for solving this problem.

share|improve this answer
I seem to have lost the access to my unregistered account... @FINESEC thanks for your reply, this is exactly what I'm doing right now, but I was wondering what – Martin Nov 6 '12 at 7:56

Not the answer you're looking for? Browse other questions tagged or ask your own question.