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>
7 For general info and legal blurb, please look in README.
9 ==============================================================
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.
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.
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
30 ..............................................................................
32 1. /proc/sys/net/core - Network core options
33 -------------------------------------------------------
38 The default setting of the socket receive buffer in bytes.
43 The maximum receive socket buffer size in bytes.
48 The default setting (in bytes) of the socket send buffer.
53 The maximum send socket buffer size in bytes.
55 message_burst and message_cost
56 ------------------------------
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
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
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 .
84 Maximum number of packets, queued on the INPUT side, when the interface
85 receives packets faster than kernel can process them.
90 Maximum ancillary buffer size allowed per socket. Ancillary data is a sequence
91 of struct cmsghdr structures with appended data.
93 2. /proc/sys/net/unix - Parameters for Unix domain sockets
94 -------------------------------------------------------
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 specified.
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.
108 -------------------------------------------------------
110 The /proc/sys/net/appletalk directory holds the Appletalk configuration data
111 when Appletalk is loaded. The configurable parameters are:
116 The amount of time we keep an ARP entry before expiring it. Used to age out
122 The amount of time we will spend trying to resolve an Appletalk address.
124 aarp-retransmit-limit
125 ---------------------
127 The number of times we will retransmit a query before giving up.
132 Controls the rate at which expires are checked.
134 The directory /proc/net/appletalk holds the list of active Appletalk sockets
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
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
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.
153 -------------------------------------------------------
155 The IPX protocol has no tunable values in proc/sys/net.
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
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
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.