# System Request functionality of the kernel (SYNC)
kernel.sysrq = 1

# Append the PID to the core filename
kernel.core_uses_pid = 1

# Source route verification
net.ipv4.conf.all.rp_filter = 1
# Do not accept source routing
net.ipv4.conf.all.accept_source_route = 0
# protection from the SYN flood attack
net.ipv4.tcp_syncookies = 1
# timestamps add a little overhead but are recommended for gbit links
net.ipv4.tcp_timestamps = 1
# ignore echo broadcast requests to prevent being part of smurf attacks
net.ipv4.icmp_echo_ignore_broadcasts = 1
# ignore bogus icmp errors
net.ipv4.icmp_ignore_bogus_error_responses = 1
# send redirects (not a router, disable it)
net.ipv4.conf.all.send_redirects = 0
# ICMP routing redirects (only secure)
net.ipv4.conf.all.accept_redirects = 0
net.ipv4.conf.all.secure_redirects = 1

# Enable hard and soft link protection
fs.protected_hardlinks = 1
fs.protected_symlinks = 1

# A little extra security for local exploits
kernel.kptr_restrict = 1