Couple of times I've mentioned the Qualsys SSL Server Test in this blog. It is a really good (currently free) tool for evaluating your TLS/SSL server's security. Typically people run it to test their web servers, but it is no way limited to that. Anyway, it is a really good tool for any sysadmin.
In general the weak link in today's Internet is DNS. People don't recognize its importance for a business. I personally would like to see DNSSEC gaining more popularity to prevent cache poisoning, perhaps I'll blog about it later. But to fight those huge DDoS-attacks there is really no other way, than to use services from a service provider who has really big guns. The second thing any sysadmin can do is to make sure, they're not part of the problem. See my earlier post about that.
Last week I found a DNS-tool equal to Qualsys' tool. Its called DNS inspect and you can use it (currently) freely at http://www.dnsinspect.com/. It is a really good tool and gives you American school grade from A to F (mostly unknown by us European peope) about the target domain inspected. I warmly recommend all admins to check their domain and DNS setup with that tool.
Both of the tools I mentioned are really good. Good to the point I'd pay money to use them. Thanks to both companies for giving out those freely.