How to Protect your Name Server ( Bind 8/9)Kernel Tuneable Security Parameters

For each tunable kernel parameters, each entry have to be added to the /etc/systcl.conf configuration file to make the change permanent after
reboots. To activate the configured kernel parameters immediately at run time, use:
# systcl -p

1. Enable TCP SYN Cookie Protection
net.ipv4.tcp_syncookies = 1

2. Disable ICMP Redirect Acceptance
net.ipv4.conf.all.accept_redirects = 0

3. Disable Source Routing
net.ipv4.conf.all.accept_souce_route = 0

4. Enable IP Spoofing Protection
net.ipv4.conf.all.rp_filter = 1

5. Enable Ignoring to ICMP Requests
net.ipv4.icmp_echo_ignore_all = 1

6. Enable Ignoring Broadcasts Requests
net.ipv4.icmp_echo_ignore_broadcasts = 1

7. Enable Ignoring Broadcasts Requests
net.ipv4.icmp_echo_ignore_bogus_error_responses = 1