# OrangeVPS hardening sysctl — /etc/sysctl.d/99-hardening.conf
# Network hardening
net.ipv4.tcp_syncookies = 1
net.ipv4.conf.all.rp_filter = 1
net.ipv4.conf.default.rp_filter = 1
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
net.ipv4.conf.all.accept_source_route = 0
net.ipv4.conf.default.accept_source_route = 0
net.ipv6.conf.all.accept_redirects = 0
net.ipv6.conf.default.accept_redirects = 0
net.ipv6.conf.all.accept_source_route = 0
net.ipv6.conf.default.accept_source_route = 0

# TCP hardening
net.ipv4.tcp_max_syn_backlog = 4096
net.ipv4.tcp_synack_retries = 2
net.ipv4.tcp_syn_retries = 3
net.ipv4.tcp_fin_timeout = 15
net.ipv4.tcp_keepalive_time = 120
net.ipv4.tcp_keepalive_intvl = 30
net.ipv4.tcp_keepalive_probes = 5
net.ipv4.tcp_tw_reuse = 1
net.ipv4.ip_local_port_range = 1024 65535

# Kernel hardening
kernel.randomize_va_space = 2
kernel.core_uses_pid = 1
kernel.dmesg_restrict = 1
kernel.kptr_restrict = 1
kernel.yama.ptrace_scope = 2
fs.protected_hardlinks = 1
fs.protected_symlinks = 1
fs.suid_dumpable = 0

# Resource limits (SYN flood protection)
net.core.somaxconn = 1024
net.core.netdev_max_backlog = 4096