|
# Kernel sysctl configuration file for Linux |
|
# |
|
# Version 1.0 |
|
# |
|
# Yohann Lepage |
|
# |
|
# Michiel Klaver - IT Professional |
|
# http://klaver.it/linux/ for the latest version - http://klaver.it/bsd/ for a BSD variant |
|
# |
|
# This file should be saved as /etc/sysctl.conf and can be activated using the command: |
|
# sysctl -e -p /etc/sysctl.conf |
|
# |
|
# For binary values, 0 is disabled, 1 is enabled. See sysctl(8) and sysctl.conf(5) for more details. |
|
# |
|
# |
|
# Intended use for dedicated server systems at high-speed networks with loads of RAM and bandwidth available |
|
# Optimised and tuned for high-performance web/ftp/mail/dns servers with high connection-rates |
|
# DO NOT USE at busy networks or xDSL/Cable connections where packetloss can be expected |
|
# ---------- |
|
|
|
|
|
|
|
### |
|
### GENERAL SYSTEM SECURITY OPTIONS ### |
|
### |
|
|
|
# Auto-reboot linux 30 seconds after a kernel panic |
|
kernel.panic = 30 |
|
kernel.panic_on_oops = 30 |
|
|
|
# Controls the System Request debugging functionality of the kernel |
|
kernel.sysrq = 0 |
|
|
|
# Controls whether core dumps will append the PID to the core filename. |
|
# Useful for debugging multi-threaded applications. |
|
kernel.core_uses_pid = 1 |
|
|
|
#Allow for more PIDs |
|
kernel.pid_max = 65536 |
|
|
|
# The contents of /proc/<pid>/maps and smaps files are only visible to |
|
# readers that are allowed to ptrace() the process |
|
kernel.maps_protect = 1 |
|
|
|
#Enable ExecShield protection |
|
kernel.exec-shield = 1 |
|
kernel.randomize_va_space = 1 |
|
|
|
# Controls the maximum size of a message, in bytes |
|
kernel.msgmnb = 65536 # 512 Kib |
|
|
|
# Controls the default maxmimum size of a mesage queue |
|
kernel.msgmax = 65536 # 512 Kib |
|
|
|
|
|
|
|
### |
|
### IMPROVE SYSTEM MEMORY MANAGEMENT ### |
|
### |
|
|
|
# Increase size of file handles and inode cache |
|
fs.file-max = 209708 |
|
|
|
# Do less swapping |
|
vm.swappiness = 10 |
|
vm.dirty_ratio = 60 |
|
vm.dirty_background_ratio = 2 |
|
|
|
# specifies the minimum virtual address that a process is allowed to mmap |
|
vm.mmap_min_addr = 4096 |
|
|
|
# No overcommitment of available memory |
|
vm.overcommit_ratio = 0 |
|
vm.overcommit_memory = 0 |
|
|
|
# Set maximum amount of memory allocated to shm to 256MB |
|
kernel.shmmax = 268435456 |
|
kernel.shmall = 268435456 |
|
|
|
# Keep at least 64MB of free RAM space available |
|
vm.min_free_kbytes = 65536 # 64 Mib |
|
|
|
|
|
|
|
### |
|
### GENERAL IPv4 NETWORK SECURITY OPTIONS ### |
|
### |
|
|
|
#Prevent SYN attack, enable SYNcookies (they will kick-in when the max_syn_backlog reached) |
|
net.ipv4.tcp_syncookies = 1 |
|
net.ipv4.tcp_syn_retries = 5 |
|
net.ipv4.tcp_synack_retries = 2 |
|
net.ipv4.tcp_max_syn_backlog = 4096 |
|
|
|
# Disables packet forwarding |
|
net.ipv4.ip_forward = 0 |
|
net.ipv4.conf.all.forwarding = 0 |
|
net.ipv4.conf.default.forwarding = 0 |
|
net.ipv6.conf.all.forwarding = 0 |
|
net.ipv6.conf.default.forwarding = 0 |
|
|
|
# Disables IP source routing |
|
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_source_route = 0 |
|
net.ipv6.conf.default.accept_source_route = 0 |
|
|
|
# Enable IP spoofing protection, turn on source route verification |
|
net.ipv4.conf.all.rp_filter = 1 |
|
net.ipv4.conf.default.rp_filter = 1 |
|
|
|
# Disable ICMP Redirect Acceptance |
|
net.ipv4.conf.all.accept_redirects = 0 |
|
net.ipv4.conf.default.accept_redirects = 0 |
|
net.ipv6.conf.all.accept_redirects = 0 |
|
net.ipv6.conf.default.accept_redirects = 0 |
|
|
|
# Disable Log Spoofed Packets, Source Routed Packets, Redirect Packets |
|
net.ipv4.conf.all.log_martians = 0 |
|
net.ipv4.conf.default.log_martians = 0 |
|
|
|
# Decrease the time default value for tcp_fin_timeout connection |
|
net.ipv4.tcp_fin_timeout = 15 |
|
|
|
# Decrease the time default value for connections to keep alive |
|
net.ipv4.tcp_keepalive_time = 300 |
|
net.ipv4.tcp_keepalive_probes = 5 |
|
net.ipv4.tcp_keepalive_intvl = 15 |
|
|
|
# Don't relay bootp |
|
net.ipv4.conf.all.bootp_relay = 0 |
|
|
|
# Don't proxy arp for anyone |
|
net.ipv4.conf.all.proxy_arp = 0 |
|
|
|
# Turn on SACK |
|
net.ipv4.tcp_dsack = 1 |
|
net.ipv4.tcp_sack = 1 |
|
net.ipv4.tcp_fack = 1 |
|
|
|
# Turn on the tcp_timestamps |
|
net.ipv4.tcp_timestamps = 1 |
|
|
|
# Don't ignore directed pings |
|
net.ipv4.icmp_echo_ignore_all = 0 |
|
|
|
# Enable ignoring broadcasts request |
|
net.ipv4.icmp_echo_ignore_broadcasts = 1 |
|
|
|
# Enable bad error message Protection |
|
net.ipv4.icmp_ignore_bogus_error_responses = 1 |
|
|
|
# Allowed local port range |
|
net.ipv4.ip_local_port_range = 16384 65536 |
|
|
|
# Enable a fix for RFC1337 - time-wait assassination hazards in TCP |
|
net.ipv4.tcp_rfc1337 = 1 |
|
|
|
|
|
|
|
### |
|
### TUNING IPv4 NETWORK PERFORMANCE ### |
|
### |
|
|
|
# Do a 'modprobe tcp_cubic' first |
|
net.ipv4.tcp_congestion_control = cubic |
|
|
|
# Turn on the tcp_window_scaling |
|
net.ipv4.tcp_window_scaling = 1 |
|
|
|
# Increase the maximum total buffer-space allocatable |
|
# This is measured in units of pages (4096 bytes) |
|
net.ipv4.tcp_mem = 65536 131072 262144 |
|
net.ipv4.udp_mem = 65536 131072 262144 |
|
|
|
# Increase the read-buffer space allocatable |
|
net.ipv4.tcp_rmem = 8192 87380 16777216 |
|
net.ipv4.udp_rmem_min = 16384 |
|
net.core.rmem_default = 131072 |
|
net.core.rmem_max = 16777216 |
|
|
|
# Increase the write-buffer-space allocatable |
|
net.ipv4.tcp_wmem = 8192 65536 16777216 |
|
net.ipv4.udp_wmem_min = 16384 |
|
net.core.wmem_default = 131072 |
|
net.core.wmem_max = 16777216 |
|
|
|
# Increase number of incoming connections |
|
net.core.somaxconn = 32768 |
|
|
|
# Increase number of incoming connections backlog |
|
net.core.netdev_max_backlog = 4096 |
|
net.core.dev_weight = 64 |
|
|
|
# Increase the maximum amount of option memory buffers |
|
net.core.optmem_max = 65536 |
|
|
|
# Increase the maximum number of skb-heads to be cached |
|
#net.core.hot_list_length = 1024 |
|
|
|
# Increase the tcp-time-wait buckets pool size to prevent simple DOS attacks |
|
net.ipv4.tcp_max_tw_buckets = 1440000 |
|
net.ipv4.tcp_tw_recycle = 1 |
|
net.ipv4.tcp_tw_reuse = 1 |
|
|
|
# Limit number of orphans, each orphan can eat up to 16M (max wmem) of unswappable memory |
|
net.ipv4.tcp_max_orphans = 16384 |
|
net.ipv4.tcp_orphan_retries = 0 |
|
|
|
# Increase the maximum memory used to reassemble IP fragments |
|
net.ipv4.ipfrag_high_thresh = 512000 |
|
net.ipv4.ipfrag_low_thresh = 446464 |
|
|
|
# don't cache ssthresh from previous connection |
|
net.ipv4.tcp_no_metrics_save = 1 |
|
net.ipv4.tcp_moderate_rcvbuf = 1 |
|
|
|
# Increase RPC slots |
|
sunrpc.tcp_slot_table_entries = 32 |
|
sunrpc.udp_slot_table_entries = 32 |
|
|
|
# Increase size of RPC datagram queue length |
|
net.unix.max_dgram_qlen = 50 |
|
|
|
# Don't allow the arp table to become bigger than this |
|
net.ipv4.neigh.default.gc_thresh3 = 2048 |
|
|
|
# Tell the gc when to become aggressive with arp table cleaning. |
|
# Adjust this based on size of the LAN. 1024 is suitable for most /24 networks |
|
net.ipv4.neigh.default.gc_thresh2 = 1024 |
|
|
|
# Adjust where the gc will leave arp table alone - set to 32. |
|
net.ipv4.neigh.default.gc_thresh1 = 32 |
|
|
|
# Adjust to arp table gc to clean-up more often |
|
net.ipv4.neigh.default.gc_interval = 30 |
|
|
|
# Increase TCP queue length |
|
net.ipv4.neigh.default.proxy_qlen = 96 |
|
net.ipv4.neigh.default.unres_qlen = 6 |
|
|
|
# Enable Explicit Congestion Notification (RFC 3168), disable it if it doesn't work for you |
|
net.ipv4.tcp_ecn = 1 |
|
net.ipv4.tcp_ecn = 2 |
|
net.ipv4.tcp_reordering = 3 |
|
|
|
# How many times to retry killing an alive TCP connection |
|
net.ipv4.tcp_retries2 = 15 |
|
net.ipv4.tcp_retries1 = 3 |
|
|
|
# This will enusre that immediatly subsequent connections use the new values |
|
net.ipv4.route.flush = 1 |
|
net.ipv6.route.flush = 1 |
|
|
|
### |
|
### TUNING IPv6 ### |
|
### |
|
net.ipv6.neigh.default.mcast_solicit = 3 |
|
net.ipv6.neigh.default.ucast_solicit = 3 |
|
net.ipv6.neigh.default.app_solicit = 0 |
|
net.ipv6.neigh.default.delay_first_probe_time = 5 |
|
net.ipv6.neigh.default.gc_stale_time = 60 |
|
net.ipv6.neigh.default.unres_qlen = 3 |
|
net.ipv6.neigh.default.proxy_qlen = 64 |
|
net.ipv6.neigh.default.anycast_delay = 99 |
|
net.ipv6.neigh.default.proxy_delay = 79 |
|
net.ipv6.neigh.default.locktime = 0 |
|
net.ipv6.neigh.default.retrans_time_ms = 1000 |
|
net.ipv6.neigh.default.base_reachable_time_ms = 30000 |
|
net.ipv6.neigh.default.gc_interval = 30 |
|
net.ipv6.neigh.default.gc_thresh1 = 128 |
|
net.ipv6.neigh.default.gc_thresh2 = 512 |
|
net.ipv6.neigh.default.gc_thresh3 = 1024 |
|
|
|
|
|
net.ipv6.xfrm6_gc_thresh = 2048 |
|
|
|
net.ipv6.conf.all.forwarding = 0 |
|
net.ipv6.conf.all.hop_limit = 64 |
|
net.ipv6.conf.all.mtu = 1280 |
|
net.ipv6.conf.all.accept_ra = 1 |
|
net.ipv6.conf.all.accept_redirects = 1 |
|
net.ipv6.conf.all.autoconf = 1 |
|
net.ipv6.conf.all.dad_transmits = 1 |
|
net.ipv6.conf.all.router_solicitations = 3 |
|
net.ipv6.conf.all.router_solicitation_interval = 4 |
|
net.ipv6.conf.all.router_solicitation_delay = 1 |
|
net.ipv6.conf.all.force_mld_version = 0 |
|
net.ipv6.conf.all.use_tempaddr = 0 |
|
net.ipv6.conf.all.temp_valid_lft = 604800 |
|
net.ipv6.conf.all.temp_prefered_lft = 86400 |
|
net.ipv6.conf.all.regen_max_retry = 5 |
|
net.ipv6.conf.all.max_desync_factor = 600 |
|
net.ipv6.conf.all.max_addresses = 16 |
|
net.ipv6.conf.all.accept_ra_defrtr = 1 |
|
net.ipv6.conf.all.accept_ra_pinfo = 1 |
|
net.ipv6.conf.all.accept_ra_rtr_pref = 1 |
|
net.ipv6.conf.all.router_probe_interval = 60 |
|
net.ipv6.conf.all.accept_ra_rt_info_max_plen = 0 |
|
net.ipv6.conf.all.proxy_ndp = 0 |
|
net.ipv6.conf.all.accept_source_route = 0 |
|
net.ipv6.conf.all.optimistic_dad = 0 |
|
net.ipv6.conf.all.mc_forwarding = 0 |
|
net.ipv6.conf.all.disable_ipv6 = 0 |
|
net.ipv6.conf.all.accept_dad = 1 |
|
net.ipv6.conf.default.forwarding = 0 |
|
net.ipv6.conf.default.hop_limit = 64 |
|
net.ipv6.conf.default.mtu = 1280 |
|
net.ipv6.conf.default.accept_ra = 1 |
|
net.ipv6.conf.default.accept_redirects = 1 |
|
net.ipv6.conf.default.autoconf = 1 |
|
net.ipv6.conf.default.dad_transmits = 1 |
|
net.ipv6.conf.default.router_solicitations = 3 |
|
net.ipv6.conf.default.router_solicitation_interval = 4 |
|
net.ipv6.conf.default.router_solicitation_delay = 1 |
|
net.ipv6.conf.default.force_mld_version = 0 |
|
net.ipv6.conf.default.use_tempaddr = 0 |
|
net.ipv6.conf.default.temp_valid_lft = 604800 |
|
net.ipv6.conf.default.temp_prefered_lft = 86400 |
|
net.ipv6.conf.default.regen_max_retry = 5 |
|
net.ipv6.conf.default.max_desync_factor = 600 |
|
net.ipv6.conf.default.max_addresses = 16 |
|
net.ipv6.conf.default.accept_ra_defrtr = 1 |
|
net.ipv6.conf.default.accept_ra_pinfo = 1 |
|
net.ipv6.conf.default.accept_ra_rtr_pref = 1 |
|
net.ipv6.conf.default.router_probe_interval = 60 |
|
net.ipv6.conf.default.accept_ra_rt_info_max_plen = 0 |
|
net.ipv6.conf.default.proxy_ndp = 0 |
|
net.ipv6.conf.default.accept_source_route = 0 |
|
net.ipv6.conf.default.optimistic_dad = 0 |
|
net.ipv6.conf.default.mc_forwarding = 0 |
|
net.ipv6.conf.default.disable_ipv6 = 0 |
|
net.ipv6.conf.default.accept_dad = 1 |
|
|
|
net.ipv6.ip6frag_high_thresh = 262144 |
|
net.ipv6.ip6frag_low_thresh = 196608 |
|
net.ipv6.ip6frag_time = 60 |
|
|
|
net.ipv6.route.gc_thresh = 1024 |
|
net.ipv6.route.max_size = 4096 |
|
net.ipv6.route.gc_min_interval = 0 |
|
net.ipv6.route.gc_timeout = 60 |
|
net.ipv6.route.gc_interval = 30 |
|
net.ipv6.route.gc_elasticity = 0 |
|
net.ipv6.route.mtu_expires = 600 |
|
net.ipv6.route.min_adv_mss = 1 |
|
net.ipv6.route.gc_min_interval_ms = 500 |
|
|
|
net.ipv6.icmp.ratelimit = 1000 |
|
net.ipv6.bindv6only = 0 |
|
net.ipv6.ip6frag_secret_interval = 600 |
|
net.ipv6.mld_max_msf = 64 |
|
|
|
### |
|
### Comments/suggestions/additions are welcome! |
|
### |