Documentation/sysctl/net.txt

   1 Documentation for /proc/sys/net/*       kernel version 2.4.0-test11-pre4
   2         (c) 1999                Terrehon Bowden <terrehon@pacbell.net>
   3                                 Bodo Bauer <bb@ricochet.net>
   4         (c) 2000                Jorge Nerin <comandante@zaralinux.com>
   5         (c) 2009                Shen Feng <shen@cn.fujitsu.com>
   6
   7 For general info and legal blurb, please look in README.
   8
   9 ==============================================================
  10
  11 This file contains the documentation for the sysctl files in
  12 /proc/sys/net and is valid for Linux kernel version 2.4.0-test11-pre4.
  13
  14 The interface  to  the  networking  parts  of  the  kernel  is  located  in
  15 /proc/sys/net. The following table shows all possible subdirectories.You may
  16 see only some of them, depending on your kernel's configuration.
  17
  18
  19 Table : Subdirectories in /proc/sys/net
  20 ..............................................................................
  21  Directory Content             Directory  Content
  22  core      General parameter   appletalk  Appletalk protocol
  23  unix      Unix domain sockets netrom     NET/ROM
  24  802       E802 protocol       ax25       AX25
  25  ethernet  Ethernet protocol   rose       X.25 PLP layer
  26  ipv4      IP version 4        x25        X.25 protocol
  27  ipx       IPX                 token-ring IBM token ring
  28  bridge    Bridging            decnet     DEC net
  29  ipv6      IP version 6
  30 ..............................................................................
  31
  32 1. /proc/sys/net/core - Network core options
  33 -------------------------------------------------------
  34
  35 rmem_default
  36 ------------
  37
  38 The default setting of the socket receive buffer in bytes.
  39
  40 rmem_max
  41 --------
  42
  43 The maximum receive socket buffer size in bytes.
  44
  45 wmem_default
  46 ------------
  47
  48 The default setting (in bytes) of the socket send buffer.
  49
  50 wmem_max
  51 --------
  52
  53 The maximum send socket buffer size in bytes.
  54
  55 message_burst and message_cost
  56 ------------------------------
  57
  58 These parameters  are used to limit the warning messages written to the kernel
  59 log from  the  networking  code.  They  enforce  a  rate  limit  to  make  a
  60 denial-of-service attack  impossible. A higher message_cost factor, results in
  61 fewer messages that will be written. Message_burst controls when messages will
  62 be dropped.  The  default  settings  limit  warning messages to one every five
  63 seconds.
  64
  65 warnings
  66 --------
  67
  68 This controls console messages from the networking stack that can occur because
  69 of problems on the network like duplicate address or bad checksums. Normally,
  70 this should be enabled, but if the problem persists the messages can be
  71 disabled.
  72
  73 netdev_budget
  74 -------------
  75
  76 Maximum number of packets taken from all interfaces in one polling cycle (NAPI
  77 poll). In one polling cycle interfaces which are registered to polling are
  78 probed in a round-robin manner. The limit of packets in one such probe can be
  79 set per-device via sysfs class/net/<device>/weight .
  80
  81 netdev_max_backlog
  82 ------------------
  83
  84 Maximum number  of  packets,  queued  on  the  INPUT  side, when the interface
  85 receives packets faster than kernel can process them.
  86
  87 optmem_max
  88 ----------
  89
  90 Maximum ancillary buffer size allowed per socket. Ancillary data is a sequence
  91 of struct cmsghdr structures with appended data.
  92
  93 2. /proc/sys/net/unix - Parameters for Unix domain sockets
  94 -------------------------------------------------------
  95
  96 There is only one file in this directory.
  97 unix_dgram_qlen limits the max number of datagrams queued in Unix domain
  98 socket's buffer. It will not take effect unless PF_UNIX flag is spicified.
  99
 100
 101 3. /proc/sys/net/ipv4 - IPV4 settings
 102 -------------------------------------------------------
 103 Please see: Documentation/networking/ip-sysctl.txt and ipvs-sysctl.txt for
 104 descriptions of these entries.
 105
 106
 107 4. Appletalk
 108 -------------------------------------------------------
 109
 110 The /proc/sys/net/appletalk  directory  holds the Appletalk configuration data
 111 when Appletalk is loaded. The configurable parameters are:
 112
 113 aarp-expiry-time
 114 ----------------
 115
 116 The amount  of  time  we keep an ARP entry before expiring it. Used to age out
 117 old hosts.
 118
 119 aarp-resolve-time
 120 -----------------
 121
 122 The amount of time we will spend trying to resolve an Appletalk address.
 123
 124 aarp-retransmit-limit
 125 ---------------------
 126
 127 The number of times we will retransmit a query before giving up.
 128
 129 aarp-tick-time
 130 --------------
 131
 132 Controls the rate at which expires are checked.
 133
 134 The directory  /proc/net/appletalk  holds the list of active Appletalk sockets
 135 on a machine.
 136
 137 The fields  indicate  the DDP type, the local address (in network:node format)
 138 the remote  address,  the  size of the transmit pending queue, the size of the
 139 received queue  (bytes waiting for applications to read) the state and the uid
 140 owning the socket.
 141
 142 /proc/net/atalk_iface lists  all  the  interfaces  configured for appletalk.It
 143 shows the  name  of the interface, its Appletalk address, the network range on
 144 that address  (or  network number for phase 1 networks), and the status of the
 145 interface.
 146
 147 /proc/net/atalk_route lists  each  known  network  route.  It lists the target
 148 (network) that the route leads to, the router (may be directly connected), the
 149 route flags, and the device the route is using.
 150
 151
 152 5. IPX
 153 -------------------------------------------------------
 154
 155 The IPX protocol has no tunable values in proc/sys/net.
 156
 157 The IPX  protocol  does,  however,  provide  proc/net/ipx. This lists each IPX
 158 socket giving  the  local  and  remote  addresses  in  Novell  format (that is
 159 network:node:port). In  accordance  with  the  strange  Novell  tradition,
 160 everything but the port is in hex. Not_Connected is displayed for sockets that
 161 are not  tied to a specific remote address. The Tx and Rx queue sizes indicate
 162 the number  of  bytes  pending  for  transmission  and  reception.  The  state
 163 indicates the  state  the  socket  is  in and the uid is the owning uid of the
 164 socket.
 165
 166 The /proc/net/ipx_interface  file lists all IPX interfaces. For each interface
 167 it gives  the network number, the node number, and indicates if the network is
 168 the primary  network.  It  also  indicates  which  device  it  is bound to (or
 169 Internal for  internal  networks)  and  the  Frame  Type if appropriate. Linux
 170 supports 802.3,  802.2,  802.2  SNAP  and DIX (Blue Book) ethernet framing for
 171 IPX.
 172
 173 The /proc/net/ipx_route  table  holds  a list of IPX routes. For each route it
 174 gives the  destination  network, the router node (or Directly) and the network
 175 address of the router (or Connected) for internal networks.