It was funny how the server is blazingly fast after I enabled APF.
Therefore, of course, Gamling.org was nuked with DDoS.
What I did is that I use Advanced Policy-based Firewall (APF) and configure to allow only specified ports.
DEVEL_MODE="0"
IG_TCP_CPORTS="21,22,25,53,80,110,143,443,3306"
IG_UDP_CPORTS="53,111"
USE_AD="1"
And I have installed Brute Force Detection (BFD) and DDoS Deflate in order to detect who nukes Gamling.org.
And I also add RootKit Hunter to check and remove Spyware from the server. (I didn't know that Linux also has Spyware :S)