# sysctl settings are defined through files in
# /usr/lib/sysctl.d/, /run/sysctl.d/, and /etc/sysctl.d/.
#
# Vendors settings live in /usr/lib/sysctl.d/.
# To override a whole file, create a new file with the same in
# /etc/sysctl.d/ and put new settings there. To override
# only specific settings, add a file with a lexically later
# name in /etc/sysctl.d/ and put new settings there.
#
# For more information, see sysctl.conf(5) and sysctl.d(5).

# Anti SYN flood
net.ipv4.tcp_syncookies = 1 net.ipv4.tcp_synack_retries = 2 net.ipv4.tcp_max_syn_backlog = 4096
# Anti spoofing
net.ipv4.conf.all.rp_filter = 1 net.ipv4.conf.default.rp_filter = 1
# Disable source routing
net.ipv4.conf.all.accept_source_route = 0 net.ipv4.conf.default.accept_source_route = 0
# Disable redirects
net.ipv4.conf.all.accept_redirects = 0 net.ipv4.conf.default.accept_redirects = 0 
net.ipv4.conf.all.send_redirects = 0 net.ipv4.conf.default.send_redirects = 0
# Ignore ICMP broadcast
net.ipv4.icmp_echo_ignore_broadcasts = 1
# Log martians
net.ipv4.conf.all.log_martians = 1
# Increase conntrack
net.netfilter.nf_conntrack_max = 262144