DDOS Protection and Shell Protection

Posted December 21, 2013 9.9k views
How do I protect my CentOS server from a DDOS and Shell attacks :L

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3 answers
You can't. The best you can do is hope to mitigate the disruption. Start w/a firewall; a non-standard port for SSH; fail2ban; SSH-key (i.e. passwordless) logins; and a monitoring tool.

For websites, CloudFlare, provides a good service (and they even have a free plan).
>> a non-standard port for SSH

This is very first thing I've done on every server or VPS I've spun up in the past couple of years. Makes a huge difference. The first time I switched off of port 22 for SSH I went from almost 10,000 attempted logins on port 22 on one day to 0 on the new port the next day.

Also really like CSF as a firewall setup tool.
you should look into a solution from Solarflare Communications. They have developed solution to protect Linux kernel from DDOS attacks.