I have settings on my network to prevent DDoSing and initially the settings were 150 packets limit for ICMP flood attack, 250 for UDP attack and 150 for TCP-SYN. But with these settings the website didn't want to open at all, so I started increasing the numbers gradually. After I set them all at 450 packets the site and the forum opened normally. Which raises the question: why does the website (and the forum) send so many packages when contacted by the user's computer? I'm not saying you're deliberately flooding the users' computers but there must be something wrong with your hosting settings and IMHO you should check them out.