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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
35bpf_jit_enable
36--------------
37
38This enables Berkeley Packet Filter Just in Time compiler.
39Currently supported on x86_64 architecture, bpf_jit provides a framework
40to speed packet filtering, the one used by tcpdump/libpcap for example.
41Values :
42 0 - disable the JIT (default value)
43 1 - enable the JIT
44 2 - enable the JIT and ask the compiler to emit traces on kernel log.
45
46rmem_default
47------------
48
49The default setting of the socket receive buffer in bytes.
50
51rmem_max
52--------
53
54The maximum receive socket buffer size in bytes.
55
56wmem_default
57------------
58
59The default setting (in bytes) of the socket send buffer.
60
61wmem_max
62--------
63
64The maximum send socket buffer size in bytes.
65
66message_burst and message_cost
67------------------------------
68
69These parameters are used to limit the warning messages written to the kernel
70log from the networking code. They enforce a rate limit to make a
71denial-of-service attack impossible. A higher message_cost factor, results in
72fewer messages that will be written. Message_burst controls when messages will
73be dropped. The default settings limit warning messages to one every five
74seconds.
75
76warnings
77--------
78
79This controls console messages from the networking stack that can occur because
80of problems on the network like duplicate address or bad checksums. Normally,
81this should be enabled, but if the problem persists the messages can be
82disabled.
83
84netdev_budget
85-------------
86
87Maximum number of packets taken from all interfaces in one polling cycle (NAPI
88poll). In one polling cycle interfaces which are registered to polling are
89probed in a round-robin manner. The limit of packets in one such probe can be
90set per-device via sysfs class/net/<device>/weight .
91
92netdev_max_backlog
93------------------
94
95Maximum number of packets, queued on the INPUT side, when the interface
96receives packets faster than kernel can process them.
97
98netdev_tstamp_prequeue
99----------------------
100
101If set to 0, RX packet timestamps can be sampled after RPS processing, when
102the target CPU processes packets. It might give some delay on timestamps, but
103permit to distribute the load on several cpus.
104
105If set to 1 (default), timestamps are sampled as soon as possible, before
106queueing.
107
108optmem_max
109----------
110
111Maximum ancillary buffer size allowed per socket. Ancillary data is a sequence
112of struct cmsghdr structures with appended data.
113
1142. /proc/sys/net/unix - Parameters for Unix domain sockets
115-------------------------------------------------------
116
117There is only one file in this directory.
118unix_dgram_qlen limits the max number of datagrams queued in Unix domain
119socket's buffer. It will not take effect unless PF_UNIX flag is specified.
120
121
1223. /proc/sys/net/ipv4 - IPV4 settings
123-------------------------------------------------------
124Please see: Documentation/networking/ip-sysctl.txt and ipvs-sysctl.txt for
125descriptions of these entries.
126
127
1284. Appletalk
129-------------------------------------------------------
130
131The /proc/sys/net/appletalk directory holds the Appletalk configuration data
132when Appletalk is loaded. The configurable parameters are:
133
134aarp-expiry-time
135----------------
136
137The amount of time we keep an ARP entry before expiring it. Used to age out
138old hosts.
139
140aarp-resolve-time
141-----------------
142
143The amount of time we will spend trying to resolve an Appletalk address.
144
145aarp-retransmit-limit
146---------------------
147
148The number of times we will retransmit a query before giving up.
149
150aarp-tick-time
151--------------
152
153Controls the rate at which expires are checked.
154
155The directory /proc/net/appletalk holds the list of active Appletalk sockets
156on a machine.
157
158The fields indicate the DDP type, the local address (in network:node format)
159the remote address, the size of the transmit pending queue, the size of the
160received queue (bytes waiting for applications to read) the state and the uid
161owning the socket.
162
163/proc/net/atalk_iface lists all the interfaces configured for appletalk.It
164shows the name of the interface, its Appletalk address, the network range on
165that address (or network number for phase 1 networks), and the status of the
166interface.
167
168/proc/net/atalk_route lists each known network route. It lists the target
169(network) that the route leads to, the router (may be directly connected), the
170route flags, and the device the route is using.
171
172
1735. IPX
174-------------------------------------------------------
175
176The IPX protocol has no tunable values in proc/sys/net.
177
178The IPX protocol does, however, provide proc/net/ipx. This lists each IPX
179socket giving the local and remote addresses in Novell format (that is
180network:node:port). In accordance with the strange Novell tradition,
181everything but the port is in hex. Not_Connected is displayed for sockets that
182are not tied to a specific remote address. The Tx and Rx queue sizes indicate
183the number of bytes pending for transmission and reception. The state
184indicates the state the socket is in and the uid is the owning uid of the
185socket.
186
187The /proc/net/ipx_interface file lists all IPX interfaces. For each interface
188it gives the network number, the node number, and indicates if the network is
189the primary network. It also indicates which device it is bound to (or
190Internal for internal networks) and the Frame Type if appropriate. Linux
191supports 802.3, 802.2, 802.2 SNAP and DIX (Blue Book) ethernet framing for
192IPX.
193
194The /proc/net/ipx_route table holds a list of IPX routes. For each route it
195gives the destination network, the router node (or Directly) and the network
196address of the router (or Connected) for internal networks.