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1Documentation 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
7For general info and legal blurb, please look in README.
8
9==============================================================
10
11This 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
14The interface to the networking parts of the kernel is located in
15/proc/sys/net. The following table shows all possible subdirectories.You may
16see only some of them, depending on your kernel's configuration.
17
18
19Table : 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
321. /proc/sys/net/core - Network core options
33-------------------------------------------------------
34
35rmem_default
36------------
37
38The default setting of the socket receive buffer in bytes.
39
40rmem_max
41--------
42
43The maximum receive socket buffer size in bytes.
44
45wmem_default
46------------
47
48The default setting (in bytes) of the socket send buffer.
49
50wmem_max
51--------
52
53The maximum send socket buffer size in bytes.
54
55message_burst and message_cost
56------------------------------
57
58These parameters are used to limit the warning messages written to the kernel
59log from the networking code. They enforce a rate limit to make a
60denial-of-service attack impossible. A higher message_cost factor, results in
61fewer messages that will be written. Message_burst controls when messages will
62be dropped. The default settings limit warning messages to one every five
63seconds.
64
65warnings
66--------
67
68This controls console messages from the networking stack that can occur because
69of problems on the network like duplicate address or bad checksums. Normally,
70this should be enabled, but if the problem persists the messages can be
71disabled.
72
73netdev_budget
74-------------
75
76Maximum number of packets taken from all interfaces in one polling cycle (NAPI
77poll). In one polling cycle interfaces which are registered to polling are
78probed in a round-robin manner. The limit of packets in one such probe can be
79set per-device via sysfs class/net/<device>/weight .
80
81netdev_max_backlog
82------------------
83
84Maximum number of packets, queued on the INPUT side, when the interface
85receives packets faster than kernel can process them.
86
87netdev_tstamp_prequeue
88----------------------
89
90If set to 0, RX packet timestamps can be sampled after RPS processing, when
91the target CPU processes packets. It might give some delay on timestamps, but
92permit to distribute the load on several cpus.
93
94If set to 1 (default), timestamps are sampled as soon as possible, before
95queueing.
96
97optmem_max
98----------
99
100Maximum ancillary buffer size allowed per socket. Ancillary data is a sequence
101of struct cmsghdr structures with appended data.
102
1032. /proc/sys/net/unix - Parameters for Unix domain sockets
104-------------------------------------------------------
105
106There is only one file in this directory.
107unix_dgram_qlen limits the max number of datagrams queued in Unix domain
108socket's buffer. It will not take effect unless PF_UNIX flag is specified.
109
110
1113. /proc/sys/net/ipv4 - IPV4 settings
112-------------------------------------------------------
113Please see: Documentation/networking/ip-sysctl.txt and ipvs-sysctl.txt for
114descriptions of these entries.
115
116
1174. Appletalk
118-------------------------------------------------------
119
120The /proc/sys/net/appletalk directory holds the Appletalk configuration data
121when Appletalk is loaded. The configurable parameters are:
122
123aarp-expiry-time
124----------------
125
126The amount of time we keep an ARP entry before expiring it. Used to age out
127old hosts.
128
129aarp-resolve-time
130-----------------
131
132The amount of time we will spend trying to resolve an Appletalk address.
133
134aarp-retransmit-limit
135---------------------
136
137The number of times we will retransmit a query before giving up.
138
139aarp-tick-time
140--------------
141
142Controls the rate at which expires are checked.
143
144The directory /proc/net/appletalk holds the list of active Appletalk sockets
145on a machine.
146
147The fields indicate the DDP type, the local address (in network:node format)
148the remote address, the size of the transmit pending queue, the size of the
149received queue (bytes waiting for applications to read) the state and the uid
150owning the socket.
151
152/proc/net/atalk_iface lists all the interfaces configured for appletalk.It
153shows the name of the interface, its Appletalk address, the network range on
154that address (or network number for phase 1 networks), and the status of the
155interface.
156
157/proc/net/atalk_route lists each known network route. It lists the target
158(network) that the route leads to, the router (may be directly connected), the
159route flags, and the device the route is using.
160
161
1625. IPX
163-------------------------------------------------------
164
165The IPX protocol has no tunable values in proc/sys/net.
166
167The IPX protocol does, however, provide proc/net/ipx. This lists each IPX
168socket giving the local and remote addresses in Novell format (that is
169network:node:port). In accordance with the strange Novell tradition,
170everything but the port is in hex. Not_Connected is displayed for sockets that
171are not tied to a specific remote address. The Tx and Rx queue sizes indicate
172the number of bytes pending for transmission and reception. The state
173indicates the state the socket is in and the uid is the owning uid of the
174socket.
175
176The /proc/net/ipx_interface file lists all IPX interfaces. For each interface
177it gives the network number, the node number, and indicates if the network is
178the primary network. It also indicates which device it is bound to (or
179Internal for internal networks) and the Frame Type if appropriate. Linux
180supports 802.3, 802.2, 802.2 SNAP and DIX (Blue Book) ethernet framing for
181IPX.
182
183The /proc/net/ipx_route table holds a list of IPX routes. For each route it
184gives the destination network, the router node (or Directly) and the network
185address of the router (or Connected) for internal networks.