Stockier network stack

Let's tighten up TCP/IP with a few resilient settings suitable for Linux servers. We'll use sysctl, the Linux runtime kernel manager. Open the sysctl configuration file:

sudo nano /etc/sysctl.conf

And add this lot:

#accept_source_route - Disable IP source routing.

net.ipv4.conf.all.accept_source_route=0
net.ipv4.conf.default.accept_source_route=0
net.ipv6.conf.all.accept_source_route=0
net.ipv6.conf.default.accept_source_route=0

#redirects - Secure the routing table.

net.ipv4.conf.all.accept_redirects=0
net.ipv6.conf.all.accept_redirects=0
net.ipv4.conf.all.send_redirects=0
net.ipv6.conf.all.send_redirects=0

#rp_filter - Prevent IP spoofing.

net.ipv4.conf.all.rp_filter=1
net.ipv4.conf.lo.rp_filter=1
net.ipv4.conf.eth0.rp_filter=1
net.ipv4.conf.default.rp_filter=1

#log_martians - Log potential attacks.

net.ipv4.conf.all.log_martians=1

#ignore_broadcasts - Avoid DoS (Smurf) attack participation.

net.ipv4.icmp_echo_ignore_broadcasts=1

#tcp_syncookies - Prevent...