Sysctl adjusts. No routing. No ipv6

# Disables packet forwarding
net.ipv4.ip_forward=0
net.ipv4.conf.all.send_redirects=0
net.ipv4.conf.default.send_redirects=0
# Disables IP source routing
net.ipv4.conf.all.accept_source_route=0
net.ipv4.conf.default.accept_source_route=0
# Accept Redirects? No, this is not router
net.ipv4.conf.all.accept_redirects=0
net.ipv4.conf.default.accept_redirects=0
# Log packets with impossible addresses to kernel log
net.ipv4.conf.all.secure_redirects=0
net.ipv4.conf.default.secure_redirects=0
# Enable Log Spoofed Packets
net.ipv4.conf.all.log_martians=1
net.ipv4.conf.default.log_martians=1
# Disables IP source routing
net.ipv4.conf.all.rp_filter=1
net.ipv4.conf.default.rp_filter=1
net.ipv4.conf.all.forwarding=0
# Ignore all ICMP ECHO and TIMESTAMP requests sent to it via broadcast/multicast
net.ipv4.icmp_echo_ignore_broadcasts=1
net.ipv4.icmp_ignore_bogus_error_responses=1
# Enable TCP SYN Cookie Protection
net.ipv4.tcp_syncookies=1
### IPv6 networking start ####
net.ipv6.conf.all.accept_ra=0
net.ipv6.conf.default.accept_ra=0
net.ipv6.conf.all.accept_redirects=0
net.ipv6.conf.default.accept_redirects=0
net.ipv6.conf.all.disable_ipv6=1
net.ipv6.conf.default.disable_ipv6=1
net.ipv6.conf.lo.disable_ipv6=1
# ExecShield
kernel.randomize_va_space = 2
# Turn off the tcp_sack
net.ipv4.tcp_sack = 0