config/etc/sysctl.conf

   1 net.ipv4.ip_forward = 1
   2 net.ipv4.ip_dynaddr = 1
   3
   4 # Disable Path MTU Discovery
   5 net.ipv4.ip_no_pmtu_disc = 1
   6
   7 net.ipv4.icmp_echo_ignore_broadcasts = 1
   8 net.ipv4.icmp_ignore_bogus_error_responses = 1
   9 net.ipv4.icmp_ratelimit = 1000
  10 net.ipv4.icmp_ratemask = 6168
  11
  12 net.ipv4.tcp_syncookies = 1
  13 net.ipv4.tcp_fin_timeout = 30
  14 net.ipv4.tcp_syn_retries = 3
  15 net.ipv4.tcp_synack_retries = 3
  16
  17 net.ipv4.conf.default.arp_filter = 1
  18 net.ipv4.conf.default.rp_filter = 0
  19 net.ipv4.conf.default.accept_redirects = 0
  20 net.ipv4.conf.default.accept_source_route = 0
  21 net.ipv4.conf.default.log_martians = 1
  22
  23 net.ipv4.conf.all.arp_filter = 1
  24 net.ipv4.conf.all.rp_filter = 0
  25 net.ipv4.conf.all.accept_redirects = 0
  26 net.ipv4.conf.all.accept_source_route = 0
  27 net.ipv4.conf.all.log_martians = 1
  28
  29 kernel.printk = 1 4 1 7
  30 vm.swappiness=1
  31 vm.mmap_min_addr = 4096
  32 vm.min_free_kbytes = 8192
  33
  34 # Disable IPv6 by default.
  35 net.ipv6.conf.all.disable_ipv6 = 1
  36 net.ipv6.conf.default.disable_ipv6 = 1
  37
  38 # Enable netfilter accounting
  39 net.netfilter.nf_conntrack_acct=1
  40
  41 # Disable netfilter on bridges.
  42 net.bridge.bridge-nf-call-ip6tables = 0
  43 net.bridge.bridge-nf-call-iptables = 0
  44 net.bridge.bridge-nf-call-arptables = 0
  45
  46 # Try to keep kernel address exposures out of various /proc files (kallsyms, modules, etc).
  47 kernel.kptr_restrict = 2
  48
  49 # Avoid kernel memory address exposures via dmesg.
  50 kernel.dmesg_restrict = 1