Linux server very slow after IP change and synflood attack

Posted by Johannes Ruof on Server Fault See other posts from Server Fault or by Johannes Ruof
Published on 2013-06-27T15:59:23Z Indexed on 2013/06/27 16:22 UTC
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linux

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ip

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change

our server experienced a synflood attack and we used the csf firewall synflood settings to block it. Our server administrators also changed the IP of the server to a new one and blackholed the old IP. The attack went over and I changed the synflood settings back. However the server is still very slow, with a very low CPU usage and very low traffic on the website. Does anybody have an idea what might be causing this?
The server is a CENTOS 6.4 x86_64
Thanks in advance,
J. Ruof

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