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 87optmem_max 88---------- 89 90Maximum ancillary buffer size allowed per socket. Ancillary data is a sequence 91of struct cmsghdr structures with appended data. 92 932. /proc/sys/net/unix - Parameters for Unix domain sockets 94------------------------------------------------------- 95 96There is only one file in this directory. 97unix_dgram_qlen limits the max number of datagrams queued in Unix domain 98socket's buffer. It will not take effect unless PF_UNIX flag is specified. 99 100 1013. /proc/sys/net/ipv4 - IPV4 settings 102------------------------------------------------------- 103Please see: Documentation/networking/ip-sysctl.txt and ipvs-sysctl.txt for 104descriptions of these entries. 105 106 1074. Appletalk 108------------------------------------------------------- 109 110The /proc/sys/net/appletalk directory holds the Appletalk configuration data 111when Appletalk is loaded. The configurable parameters are: 112 113aarp-expiry-time 114---------------- 115 116The amount of time we keep an ARP entry before expiring it. Used to age out 117old hosts. 118 119aarp-resolve-time 120----------------- 121 122The amount of time we will spend trying to resolve an Appletalk address. 123 124aarp-retransmit-limit 125--------------------- 126 127The number of times we will retransmit a query before giving up. 128 129aarp-tick-time 130-------------- 131 132Controls the rate at which expires are checked. 133 134The directory /proc/net/appletalk holds the list of active Appletalk sockets 135on a machine. 136 137The fields indicate the DDP type, the local address (in network:node format) 138the remote address, the size of the transmit pending queue, the size of the 139received queue (bytes waiting for applications to read) the state and the uid 140owning the socket. 141 142/proc/net/atalk_iface lists all the interfaces configured for appletalk.It 143shows the name of the interface, its Appletalk address, the network range on 144that address (or network number for phase 1 networks), and the status of the 145interface. 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 149route flags, and the device the route is using. 150 151 1525. IPX 153------------------------------------------------------- 154 155The IPX protocol has no tunable values in proc/sys/net. 156 157The IPX protocol does, however, provide proc/net/ipx. This lists each IPX 158socket giving the local and remote addresses in Novell format (that is 159network:node:port). In accordance with the strange Novell tradition, 160everything but the port is in hex. Not_Connected is displayed for sockets that 161are not tied to a specific remote address. The Tx and Rx queue sizes indicate 162the number of bytes pending for transmission and reception. The state 163indicates the state the socket is in and the uid is the owning uid of the 164socket. 165 166The /proc/net/ipx_interface file lists all IPX interfaces. For each interface 167it gives the network number, the node number, and indicates if the network is 168the primary network. It also indicates which device it is bound to (or 169Internal for internal networks) and the Frame Type if appropriate. Linux 170supports 802.3, 802.2, 802.2 SNAP and DIX (Blue Book) ethernet framing for 171IPX. 172 173The /proc/net/ipx_route table holds a list of IPX routes. For each route it 174gives the destination network, the router node (or Directly) and the network 175address of the router (or Connected) for internal networks. 176