الحماية ضد Dos , DDos +تقوية sysctl.conf و host.conf

cd /root
rm -fv csf.tgz
wget http://www.configserver.com/free/csf.tgz
tar -xzf csf.tgz
cd csf
sh install.sh

cd /etc/ 
mv sysctl.conf sysctl.conf.css  

pico sysctl.conf

# Kernel sysctl configuration file for Red Hat Linux 
# 
# For binary values, 0 is disabled, 1 is enabled.  See sysctl(8) and 
# sysctl.conf(5) for more details. 

# Controls IP packet forwarding 
net.ipv4.ip_forward = 0 

# Controls source route verification 
net.ipv4.conf.default.rp_filter = 1 
net.ipv4.conf.all.rp_filter = 1 
net.ipv4.conf.lo.rp_filter = 1 
net.ipv4.conf.eth0.rp_filter = 1 

# Do not accept source routing 
net.ipv4.conf.default.accept_source_route = 0 
net.ipv4.conf.all.accept_source_route = 0 
net.ipv4.conf.lo.accept_source_route = 0 
net.ipv4.conf.eth0.accept_source_route = 0 

# Disable ICMP Redirect Acceptance 
net.ipv4.conf.all.accept_redirects = 0 
net.ipv4.conf.lo.accept_redirects = 0 
net.ipv4.conf.eth0.accept_redirects = 0 
net.ipv4.conf.default.accept_redirects = 0 

# Enable Log Spoofed Packets, Source Routed Packets, Redirect Packets 
net.ipv4.conf.all.log_martians = 0 
net.ipv4.conf.lo.log_martians = 0 
net.ipv4.conf.eth0.log_martians = 0 

# Lower retry rates 
net.ipv4.tcp_synack_retries = 2 
net.ipv4.tcp_syn_retries = 3 

# Controls the System Request debugging functionality of the kernel 
kernel.sysrq = 0 

# Max File Handlers 
fs.file-max = 8192 
# Disable CTR+ALT+DEL Restart Keys 
kernel.ctrl-alt-del = 1 

# Controls whether core dumps will append the PID to the core filename. 
# Useful for debugging multi-threaded applications. 
kernel.core_uses_pid = 1 

# Decrease the time default value for tcp_fin_timeout connection 
net.ipv4.tcp_fin_timeout = 15 

# Decrease the time default value for tcp_keepalive_time connection 
net.ipv4.tcp_keepalive_time = 1800 

# Turn off the tcp_window_scaling 
net.ipv4.tcp_window_scaling = 0 

# Turn off the tcp_sack 
net.ipv4.tcp_sack = 0 

# Turn off the tcp_timestamps 
net.ipv4.tcp_timestamps = 0 

# Enable TCP SYN معهد الحمايه العربىمعهد الحمايه العربىمعهد الحمايه العربىمعهد الحمايه العربىمعهد الحمايه العربىe Protection 
net.ipv4.tcp_synمعهد الحمايه العربىمعهد الحمايه العربىمعهد الحمايه العربىمعهد الحمايه العربىمعهد الحمايه العربىes = 1 

# Enable ignoring broadcasts request 
net.ipv4.icmp_echo_ignore_broadcasts = 1 

# Enable bad error message Protection 
net.ipv4.icmp_ignore_bogus_error_responses = 1 

# Log Spoofed Packets, Source Routed Packets, Redirect Packets 
net.ipv4.conf.all.log_martians = 1 

# Increases the size of the socket queue (effectively, q0). 
net.ipv4.tcp_max_syn_backlog = 1024 

# Increase the tcp-time-wait buckets pool size 
net.ipv4.tcp_max_tw_buckets = 1440000 

# Allowed local port range 
net.ipv4.ip_local_port_range = 16384 65536

cd /etc 
mv  host.conf  host.conf.css

pico host.conf

# Lookup names via DNS first then fall back to /etc/hosts 
order hosts,bind 
# Check for IP address spoofing. 
nospoof on 
# multiple IP addresses 
multi on

cd /usr/local/src
wget http://www.nuclearelephant.com/proje..._1.10.1.tar.gz
tar -zxvf mod_evasive_1.10.1.tar.gz
cd mod_evasive

/usr/sbin/apxs -cia mod_evasive20.c

<IfModule mod_evasive20.c>
DOSHashTableSize 3097
DOSPageCount 6
DOSSiteCount 100
DOSPageInterval 2
DOSSiteInterval 2
DOSBlockingPeriod 600
</IfModule>

httpd restart