Documentation / sysctl / net.txt
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Based on kernel version 3.9. Page generated on 2013-05-02 23:15 EST.
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 bpf_jit_enable 36 -------------- 37 38 This enables Berkeley Packet Filter Just in Time compiler. 39 Currently supported on x86_64 architecture, bpf_jit provides a framework 40 to speed packet filtering, the one used by tcpdump/libpcap for example. 41 Values : 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 46 dev_weight 47 -------------- 48 49 The maximum number of packets that kernel can handle on a NAPI interrupt, 50 it's a Per-CPU variable. 51 Default: 64 52 53 rmem_default 54 ------------ 55 56 The default setting of the socket receive buffer in bytes. 57 58 rmem_max 59 -------- 60 61 The maximum receive socket buffer size in bytes. 62 63 wmem_default 64 ------------ 65 66 The default setting (in bytes) of the socket send buffer. 67 68 wmem_max 69 -------- 70 71 The maximum send socket buffer size in bytes. 72 73 message_burst and message_cost 74 ------------------------------ 75 76 These parameters are used to limit the warning messages written to the kernel 77 log from the networking code. They enforce a rate limit to make a 78 denial-of-service attack impossible. A higher message_cost factor, results in 79 fewer messages that will be written. Message_burst controls when messages will 80 be dropped. The default settings limit warning messages to one every five 81 seconds. 82 83 warnings 84 -------- 85 86 This controls console messages from the networking stack that can occur because 87 of problems on the network like duplicate address or bad checksums. Normally, 88 this should be enabled, but if the problem persists the messages can be 89 disabled. 90 91 netdev_budget 92 ------------- 93 94 Maximum number of packets taken from all interfaces in one polling cycle (NAPI 95 poll). In one polling cycle interfaces which are registered to polling are 96 probed in a round-robin manner. The limit of packets in one such probe can be 97 set per-device via sysfs class/net/<device>/weight . 98 99 netdev_max_backlog 100 ------------------ 101 102 Maximum number of packets, queued on the INPUT side, when the interface 103 receives packets faster than kernel can process them. 104 105 netdev_tstamp_prequeue 106 ---------------------- 107 108 If set to 0, RX packet timestamps can be sampled after RPS processing, when 109 the target CPU processes packets. It might give some delay on timestamps, but 110 permit to distribute the load on several cpus. 111 112 If set to 1 (default), timestamps are sampled as soon as possible, before 113 queueing. 114 115 optmem_max 116 ---------- 117 118 Maximum ancillary buffer size allowed per socket. Ancillary data is a sequence 119 of struct cmsghdr structures with appended data. 120 121 2. /proc/sys/net/unix - Parameters for Unix domain sockets 122 ------------------------------------------------------- 123 124 There is only one file in this directory. 125 unix_dgram_qlen limits the max number of datagrams queued in Unix domain 126 socket's buffer. It will not take effect unless PF_UNIX flag is specified. 127 128 129 3. /proc/sys/net/ipv4 - IPV4 settings 130 ------------------------------------------------------- 131 Please see: Documentation/networking/ip-sysctl.txt and ipvs-sysctl.txt for 132 descriptions of these entries. 133 134 135 4. Appletalk 136 ------------------------------------------------------- 137 138 The /proc/sys/net/appletalk directory holds the Appletalk configuration data 139 when Appletalk is loaded. The configurable parameters are: 140 141 aarp-expiry-time 142 ---------------- 143 144 The amount of time we keep an ARP entry before expiring it. Used to age out 145 old hosts. 146 147 aarp-resolve-time 148 ----------------- 149 150 The amount of time we will spend trying to resolve an Appletalk address. 151 152 aarp-retransmit-limit 153 --------------------- 154 155 The number of times we will retransmit a query before giving up. 156 157 aarp-tick-time 158 -------------- 159 160 Controls the rate at which expires are checked. 161 162 The directory /proc/net/appletalk holds the list of active Appletalk sockets 163 on a machine. 164 165 The fields indicate the DDP type, the local address (in network:node format) 166 the remote address, the size of the transmit pending queue, the size of the 167 received queue (bytes waiting for applications to read) the state and the uid 168 owning the socket. 169 170 /proc/net/atalk_iface lists all the interfaces configured for appletalk.It 171 shows the name of the interface, its Appletalk address, the network range on 172 that address (or network number for phase 1 networks), and the status of the 173 interface. 174 175 /proc/net/atalk_route lists each known network route. It lists the target 176 (network) that the route leads to, the router (may be directly connected), the 177 route flags, and the device the route is using. 178 179 180 5. IPX 181 ------------------------------------------------------- 182 183 The IPX protocol has no tunable values in proc/sys/net. 184 185 The IPX protocol does, however, provide proc/net/ipx. This lists each IPX 186 socket giving the local and remote addresses in Novell format (that is 187 network:node:port). In accordance with the strange Novell tradition, 188 everything but the port is in hex. Not_Connected is displayed for sockets that 189 are not tied to a specific remote address. The Tx and Rx queue sizes indicate 190 the number of bytes pending for transmission and reception. The state 191 indicates the state the socket is in and the uid is the owning uid of the 192 socket. 193 194 The /proc/net/ipx_interface file lists all IPX interfaces. For each interface 195 it gives the network number, the node number, and indicates if the network is 196 the primary network. It also indicates which device it is bound to (or 197 Internal for internal networks) and the Frame Type if appropriate. Linux 198 supports 802.3, 802.2, 802.2 SNAP and DIX (Blue Book) ethernet framing for 199 IPX. 200 201 The /proc/net/ipx_route table holds a list of IPX routes. For each route it 202 gives the destination network, the router node (or Directly) and the network 203 address of the router (or Connected) for internal networks.
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