doc/user/Useful_Sysctl_Settings.md

   1 # Useful Sysctl Settings
   2 Sysctl on Linux systems can tweak many useful behaviors. When it comes to a routing protocol suite like FRRouting there are numerous values depending on your use case that make sense to optimize.
   3
   4 The below sysctl values provide a logical set of defaults which can be further optimized.
   5
   6
   7 ```
   8 # /etc/sysctl.d/99frr_defaults.conf
   9 # Place this file at the location above and reload the device.
  10 # or run the sysctl -p /etc/sysctl.d/99frr_defaults.conf
  11
  12 # Enables IPv4/IPv6 Routing
  13 net.ipv4.ip_forward = 1
  14 net.ipv6.conf.all.forwarding=1
  15
  16 # Routing
  17 net.ipv6.route.max_size=131072
  18 net.ipv4.conf.all.ignore_routes_with_linkdown=1
  19 net.ipv6.conf.all.ignore_routes_with_linkdown=1
  20
  21 # Best Settings for Peering w/ BGP Unnumbered
  22 #    and OSPF Neighbors
  23 net.ipv4.conf.all.rp_filter = 0
  24 net.ipv4.conf.default.rp_filter = 0
  25 net.ipv4.conf.lo.rp_filter = 0
  26 net.ipv4.conf.all.forwarding = 1
  27 net.ipv4.conf.default.forwarding = 1
  28 net.ipv4.conf.default.arp_announce = 2
  29 net.ipv4.conf.default.arp_notify = 1
  30 net.ipv4.conf.default.arp_ignore=1
  31 net.ipv4.conf.all.arp_announce = 2
  32 net.ipv4.conf.all.arp_notify = 1
  33 net.ipv4.conf.all.arp_ignore=1
  34 net.ipv4.icmp_errors_use_inbound_ifaddr=1
  35
  36 # Miscellaneous Settings
  37
  38 #   Keep ipv6 permanent addresses on an admin down
  39 net.ipv6.conf.all.keep_addr_on_down=1
  40
  41 # igmp
  42 net.ipv4.igmp_max_memberships=1000
  43 net.ipv4.neigh.default.mcast_solicit = 10
  44
  45 # MLD
  46 net.ipv6.mld_max_msf=512
  47
  48 # Garbage Collection Settings for ARP and Neighbors
  49 net.ipv4.neigh.default.gc_thresh2=7168
  50 net.ipv4.neigh.default.gc_thresh3=8192
  51 net.ipv4.neigh.default.base_reachable_time_ms=14400000
  52 net.ipv6.neigh.default.gc_thresh2=3584
  53 net.ipv6.neigh.default.gc_thresh3=4096
  54 net.ipv6.neigh.default.base_reachable_time_ms=14400000
  55
  56 # Use neigh information on selection of nexthop for multipath hops
  57 net.ipv4.fib_multipath_use_neigh=1
  58
  59 # Allows Apps to Work with VRF
  60 net.ipv4.tcp_l3mdev_accept=1
  61 ```