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My questions are:

1.) What is a recommended "SYN PROXY SERVER" to filter bogus SYN Attacks and only forward "handshaked" valid connections to the host behind it (to be protected). I search the term, but did not find any direct hits/products,preferably open source/free?

2.) If there are not "ready built" Syn Proxy Servers, how can I build my own (with iptables?)

3.) Are Syn Proxy Servers recommended and usefull? Does anyone have any experience with it? (I otherwise might youse syncookies...)

Thanks very much! Markus

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A SYN proxy server is nothing more than a bastion host that are setup to handle an awful lot of incoming half-built TCP connections, and only pass-off the completed ones. I honestly have no idea why you would use one; they're still vulnerable to failure by resource exhaustion (they've still got a finite amount of state space) and hence don't scale nearly as well as a good SYN cookie implementation.

Out of interest, can you share the source of your recommendation for a SYN proxy server?

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Good Question: It's germanies (at least amongst the real IT geeks;-) most renowned Computer magazine called "ct". I never heard of the term "syn proxy" but as they mentioned it, I thought this must be someting very important I have to check out... – Markus Aug 27 '11 at 19:59
Journalists are rarely the people you want to be relying on for technology advice. – womble Aug 27 '11 at 21:50
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