# # Network configuration # menu "Networking support" config NET bool "Networking support" ---help--- Unless you really know what you are doing, you should say Y here. The reason is that some programs need kernel networking support even when running on a stand-alone machine that isn't connected to any other computer. If you are upgrading from an older kernel, you should consider updating your networking tools too because changes in the kernel and the tools often go hand in hand. The tools are contained in the package net-tools, the location and version number of which are given in . For a general introduction to Linux networking, it is highly recommended to read the NET-HOWTO, available from . menu "Networking options" depends on NET config PACKET tristate "Packet socket" ---help--- The Packet protocol is used by applications which communicate directly with network devices without an intermediate network protocol implemented in the kernel, e.g. tcpdump. If you want them to work, choose Y. To compile this driver as a module, choose M here: the module will be called af_packet. If unsure, say Y. config PACKET_MMAP bool "Packet socket: mmapped IO" depends on PACKET help If you say Y here, the Packet protocol driver will use an IO mechanism that results in faster communication. If unsure, say N. config NETLINK_DEV tristate "Netlink device emulation" help This option will be removed soon. Any programs that want to use character special nodes like /dev/tap0 or /dev/route (all with major number 36) need this option, and need to be rewritten soon to use the real netlink socket. This is a backward compatibility option, choose Y for now. config UNIX tristate "Unix domain sockets" ---help--- If you say Y here, you will include support for Unix domain sockets; sockets are the standard Unix mechanism for establishing and accessing network connections. Many commonly used programs such as the X Window system and syslog use these sockets even if your machine is not connected to any network. Unless you are working on an embedded system or something similar, you therefore definitely want to say Y here. To compile this driver as a module, choose M here: the module will be called unix. Note that several important services won't work correctly if you say M here and then neglect to load the module. Say Y unless you know what you are doing. config NET_KEY tristate "PF_KEY sockets" select XFRM ---help--- PF_KEYv2 socket family, compatible to KAME ones. They are required if you are going to use IPsec tools ported from KAME. Say Y unless you know what you are doing. config INET bool "TCP/IP networking" ---help--- These are the protocols used on the Internet and on most local Ethernets. It is highly recommended to say Y here (this will enlarge your kernel by about 144 KB), since some programs (e.g. the X window system) use TCP/IP even if your machine is not connected to any other computer. You will get the so-called loopback device which allows you to ping yourself (great fun, that!). For an excellent introduction to Linux networking, please read the Linux Networking HOWTO, available from . If you say Y here and also to "/proc file system support" and "Sysctl support" below, you can change various aspects of the behavior of the TCP/IP code by writing to the (virtual) files in /proc/sys/net/ipv4/*; the options are explained in the file . Short answer: say Y. source "net/ipv4/Kconfig" # IPv6 as module will cause a CRASH if you try to unload it config IPV6 tristate "The IPv6 protocol (EXPERIMENTAL)" depends on INET && EXPERIMENTAL ---help--- This is experimental support for the IP version 6 (formerly called IPng "IP next generation"). You will still be able to do regular IPv4 networking as well. Features of this new protocol include: expanded address space, authentication and privacy, and seamless interoperability with the current version of IP (IP version 4). For general information about IPv6, see ; for specific information about IPv6 under Linux read the HOWTO at and the file net/ipv6/README in the kernel source. To compile this protocol support as a module, choose M here: the module will be called ipv6. It is safe to say N here for now. source "net/ipv6/Kconfig" menuconfig NETFILTER bool "Network packet filtering (replaces ipchains)" ---help--- Netfilter is a framework for filtering and mangling network packets that pass through your Linux box. The most common use of packet filtering is to run your Linux box as a firewall protecting a local network from the Internet. The type of firewall provided by this kernel support is called a "packet filter", which means that it can reject individual network packets based on type, source, destination etc. The other kind of firewall, a "proxy-based" one, is more secure but more intrusive and more bothersome to set up; it inspects the network traffic much more closely, modifies it and has knowledge about the higher level protocols, which a packet filter lacks. Moreover, proxy-based firewalls often require changes to the programs running on the local clients. Proxy-based firewalls don't need support by the kernel, but they are often combined with a packet filter, which only works if you say Y here. You should also say Y here if you intend to use your Linux box as the gateway to the Internet for a local network of machines without globally valid IP addresses. This is called "masquerading": if one of the computers on your local network wants to send something to the outside, your box can "masquerade" as that computer, i.e. it forwards the traffic to the intended outside destination, but modifies the packets to make it look like they came from the firewall box itself. It works both ways: if the outside host replies, the Linux box will silently forward the traffic to the correct local computer. This way, the computers on your local net are completely invisible to the outside world, even though they can reach the outside and can receive replies. It is even possible to run globally visible servers from within a masqueraded local network using a mechanism called portforwarding. Masquerading is also often called NAT (Network Address Translation). Another use of Netfilter is in transparent proxying: if a machine on the local network tries to connect to an outside host, your Linux box can transparently forward the traffic to a local server, typically a caching proxy server. Yet another use of Netfilter is building a bridging firewall. Using a bridge with Network packet filtering enabled makes iptables "see" the bridged traffic. For filtering on the lower network and Ethernet protocols over the bridge, use ebtables (under bridge netfilter configuration). Various modules exist for netfilter which replace the previous masquerading (ipmasqadm), packet filtering (ipchains), transparent proxying, and portforwarding mechanisms. Please see under "iptables" for the location of these packages. Make sure to say N to "Fast switching" below if you intend to say Y here, as Fast switching currently bypasses netfilter. Chances are that you should say Y here if you compile a kernel which will run as a router and N for regular hosts. If unsure, say N. if NETFILTER config NETFILTER_DEBUG bool "Network packet filtering debugging" depends on NETFILTER help You can say Y here if you want to get additional messages useful in debugging the netfilter code. config BRIDGE_NETFILTER bool "Bridged IP/ARP packets filtering" depends on BRIDGE && NETFILTER && INET default y ---help--- Enabling this option will let arptables resp. iptables see bridged ARP resp. IP traffic. If you want a bridging firewall, you probably want this option enabled. Enabling or disabling this option doesn't enable or disable ebtables. If unsure, say N. source "net/ipv4/netfilter/Kconfig" source "net/ipv6/netfilter/Kconfig" source "net/decnet/netfilter/Kconfig" source "net/bridge/netfilter/Kconfig" endif source "net/xfrm/Kconfig" source "net/sctp/Kconfig" config ATM tristate "Asynchronous Transfer Mode (ATM) (EXPERIMENTAL)" depends on EXPERIMENTAL ---help--- ATM is a high-speed networking technology for Local Area Networks and Wide Area Networks. It uses a fixed packet size and is connection oriented, allowing for the negotiation of minimum bandwidth requirements. In order to participate in an ATM network, your Linux box needs an ATM networking card. If you have that, say Y here and to the driver of your ATM card below. Note that you need a set of user-space programs to actually make use of ATM. See the file for further details. config ATM_CLIP tristate "Classical IP over ATM (EXPERIMENTAL)" depends on ATM && INET help Classical IP over ATM for PVCs and SVCs, supporting InARP and ATMARP. If you want to communication with other IP hosts on your ATM network, you will typically either say Y here or to "LAN Emulation (LANE)" below. config ATM_CLIP_NO_ICMP bool "Do NOT send ICMP if no neighbour (EXPERIMENTAL)" depends on ATM_CLIP help Normally, an "ICMP host unreachable" message is sent if a neighbour cannot be reached because there is no VC to it in the kernel's ATMARP table. This may cause problems when ATMARP table entries are briefly removed during revalidation. If you say Y here, packets to such neighbours are silently discarded instead. config ATM_LANE tristate "LAN Emulation (LANE) support (EXPERIMENTAL)" depends on ATM help LAN Emulation emulates services of existing LANs across an ATM network. Besides operating as a normal ATM end station client, Linux LANE client can also act as an proxy client bridging packets between ELAN and Ethernet segments. You need LANE if you want to try MPOA. config ATM_MPOA tristate "Multi-Protocol Over ATM (MPOA) support (EXPERIMENTAL)" depends on ATM && INET && ATM_LANE!=n help Multi-Protocol Over ATM allows ATM edge devices such as routers, bridges and ATM attached hosts establish direct ATM VCs across subnetwork boundaries. These shortcut connections bypass routers enhancing overall network performance. config ATM_BR2684 tristate "RFC1483/2684 Bridged protocols" depends on ATM && INET help ATM PVCs can carry ethernet PDUs according to rfc2684 (formerly 1483) This device will act like an ethernet from the kernels point of view, with the traffic being carried by ATM PVCs (currently 1 PVC/device). This is sometimes used over DSL lines. If in doubt, say N. config ATM_BR2684_IPFILTER bool "Per-VC IP filter kludge" depends on ATM_BR2684 help This is an experimental mechanism for users who need to terminating a large number of IP-only vcc's. Do not enable this unless you are sure you know what you are doing. config BRIDGE tristate "802.1d Ethernet Bridging" ---help--- If you say Y here, then your Linux box will be able to act as an Ethernet bridge, which means that the different Ethernet segments it is connected to will appear as one Ethernet to the participants. Several such bridges can work together to create even larger networks of Ethernets using the IEEE 802.1 spanning tree algorithm. As this is a standard, Linux bridges will cooperate properly with other third party bridge products. In order to use the Ethernet bridge, you'll need the bridge configuration tools; see for location. Please read the Bridge mini-HOWTO for more information. If you enable iptables support along with the bridge support then you turn your bridge into a bridging IP firewall. iptables will then see the IP packets being bridged, so you need to take this into account when setting up your firewall rules. Enabling arptables support when bridging will let arptables see bridged ARP traffic in the arptables FORWARD chain. To compile this code as a module, choose M here: the module will be called bridge. If unsure, say N. config VLAN_8021Q tristate "802.1Q VLAN Support" config DECNET tristate "DECnet Support" ---help--- The DECnet networking protocol was used in many products made by Digital (now Compaq). It provides reliable stream and sequenced packet communications over which run a variety of services similar to those which run over TCP/IP. To find some tools to use with the kernel layer support, please look at Patrick Caulfield's web site: . More detailed documentation is available in . Be sure to say Y to "/proc file system support" and "Sysctl support" below when using DECnet, since you will need sysctl support to aid in configuration at run time. The DECnet code is also available as a module ( = code which can be inserted in and removed from the running kernel whenever you want). The module is called decnet. source "net/decnet/Kconfig" source "net/llc/Kconfig" config IPX tristate "The IPX protocol" select LLC ---help--- This is support for the Novell networking protocol, IPX, commonly used for local networks of Windows machines. You need it if you want to access Novell NetWare file or print servers using the Linux Novell client ncpfs (available from ) or from within the Linux DOS emulator DOSEMU (read the DOSEMU-HOWTO, available from ). In order to do the former, you'll also have to say Y to "NCP file system support", below. IPX is similar in scope to IP, while SPX, which runs on top of IPX, is similar to TCP. There is also experimental support for SPX in Linux (see "SPX networking", below). To turn your Linux box into a fully featured NetWare file server and IPX router, say Y here and fetch either lwared from or mars_nwe from . For more information, read the IPX-HOWTO available from . General information about how to connect Linux, Windows machines and Macs is on the WWW at . The IPX driver would enlarge your kernel by about 16 KB. To compile this driver as a module, choose M here: the module will be called ipx. Unless you want to integrate your Linux box with a local Novell network, say N. source "net/ipx/Kconfig" config ATALK tristate "Appletalk protocol support" select LLC ---help--- AppleTalk is the protocol that Apple computers can use to communicate on a network. If your Linux box is connected to such a network and you wish to connect to it, say Y. You will need to use the netatalk package so that your Linux box can act as a print and file server for Macs as well as access AppleTalk printers. Check out on the WWW for details. EtherTalk is the name used for AppleTalk over Ethernet and the cheaper and slower LocalTalk is AppleTalk over a proprietary Apple network using serial links. EtherTalk and LocalTalk are fully supported by Linux. General information about how to connect Linux, Windows machines and Macs is on the WWW at . The NET-3-HOWTO, available from , contains valuable information as well. To compile this driver as a module, choose M here: the module will be called appletalk. You almost certainly want to compile it as a module so you can restart your AppleTalk stack without rebooting your machine. I hear that the GNU boycott of Apple is over, so even politically correct people are allowed to say Y here. source "drivers/net/appletalk/Kconfig" config X25 tristate "CCITT X.25 Packet Layer (EXPERIMENTAL)" depends on EXPERIMENTAL ---help--- X.25 is a set of standardized network protocols, similar in scope to frame relay; the one physical line from your box to the X.25 network entry point can carry several logical point-to-point connections (called "virtual circuits") to other computers connected to the X.25 network. Governments, banks, and other organizations tend to use it to connect to each other or to form Wide Area Networks (WANs). Many countries have public X.25 networks. X.25 consists of two protocols: the higher level Packet Layer Protocol (PLP) (say Y here if you want that) and the lower level data link layer protocol LAPB (say Y to "LAPB Data Link Driver" below if you want that). You can read more about X.25 at and . Information about X.25 for Linux is contained in the files and . One connects to an X.25 network either with a dedicated network card using the X.21 protocol (not yet supported by Linux) or one can do X.25 over a standard telephone line using an ordinary modem (say Y to "X.25 async driver" below) or over Ethernet using an ordinary Ethernet card and the LAPB over Ethernet (say Y to "LAPB Data Link Driver" and "LAPB over Ethernet driver" below). To compile this driver as a module, choose M here: the module will be called x25. If unsure, say N. config LAPB tristate "LAPB Data Link Driver (EXPERIMENTAL)" depends on EXPERIMENTAL ---help--- Link Access Procedure, Balanced (LAPB) is the data link layer (i.e. the lower) part of the X.25 protocol. It offers a reliable connection service to exchange data frames with one other host, and it is used to transport higher level protocols (mostly X.25 Packet Layer, the higher part of X.25, but others are possible as well). Usually, LAPB is used with specialized X.21 network cards, but Linux currently supports LAPB only over Ethernet connections. If you want to use LAPB connections over Ethernet, say Y here and to "LAPB over Ethernet driver" below. Read for technical details. To compile this driver as a module, choose M here: the module will be called lapb. If unsure, say N. config NET_DIVERT bool "Frame Diverter (EXPERIMENTAL)" depends on EXPERIMENTAL ---help--- The Frame Diverter allows you to divert packets from the network, that are not aimed at the interface receiving it (in promisc. mode). Typically, a Linux box setup as an Ethernet bridge with the Frames Diverter on, can do some *really* transparent www caching using a Squid proxy for example. This is very useful when you don't want to change your router's config (or if you simply don't have access to it). The other possible usages of diverting Ethernet Frames are numberous: - reroute smtp traffic to another interface - traffic-shape certain network streams - transparently proxy smtp connections - etc... For more informations, please refer to: If unsure, say N. config ECONET tristate "Acorn Econet/AUN protocols (EXPERIMENTAL)" depends on EXPERIMENTAL && INET ---help--- Econet is a fairly old and slow networking protocol mainly used by Acorn computers to access file and print servers. It uses native Econet network cards. AUN is an implementation of the higher level parts of Econet that runs over ordinary Ethernet connections, on top of the UDP packet protocol, which in turn runs on top of the Internet protocol IP. If you say Y here, you can choose with the next two options whether to send Econet/AUN traffic over a UDP Ethernet connection or over a native Econet network card. To compile this driver as a module, choose M here: the module will be called econet. config ECONET_AUNUDP bool "AUN over UDP" depends on ECONET help Say Y here if you want to send Econet/AUN traffic over a UDP connection (UDP is a packet based protocol that runs on top of the Internet protocol IP) using an ordinary Ethernet network card. config ECONET_NATIVE bool "Native Econet" depends on ECONET help Say Y here if you have a native Econet network card installed in your computer. config WAN_ROUTER tristate "WAN router" depends on EXPERIMENTAL ---help--- Wide Area Networks (WANs), such as X.25, frame relay and leased lines, are used to interconnect Local Area Networks (LANs) over vast distances with data transfer rates significantly higher than those achievable with commonly used asynchronous modem connections. Usually, a quite expensive external device called a `WAN router' is needed to connect to a WAN. As an alternative, WAN routing can be built into the Linux kernel. With relatively inexpensive WAN interface cards available on the market, a perfectly usable router can be built for less than half the price of an external router. If you have one of those cards and wish to use your Linux box as a WAN router, say Y here and also to the WAN driver for your card, below. You will then need the wan-tools package which is available from . Read for more information. To compile WAN routing support as a module, choose M here: the module will be called wanrouter. If unsure, say N. config NET_FASTROUTE bool "Fast switching (read help!)" depends on EXPERIMENTAL ---help--- Saying Y here enables direct NIC-to-NIC (NIC = Network Interface Card) data transfers on the local network, which is fast. IMPORTANT NOTE: This option is NOT COMPATIBLE with "Network packet filtering" (CONFIG_NETFILTER). Say N here if you say Y there. However, it will work with all options in the "Advanced router" section (except for "Use TOS value as routing key" and "Use FWMARK value as routing key"). At the moment, few devices support fast switching (tulip is one of them, a modified 8390 driver can be found at ). If unsure, say N. config NET_HW_FLOWCONTROL bool "Forwarding between high speed interfaces" depends on EXPERIMENTAL ---help--- This option enables NIC (Network Interface Card) hardware throttling during periods of extreme congestion. At the moment only a couple of device drivers support it (really only one -- tulip, a modified 8390 driver can be found at ). Really, this option is applicable to any machine attached to a fast enough network, and even a 10 Mb NIC is able to kill a not very slow box, such as a 120MHz Pentium. However, do not say Y here if you did not experience any serious problems. menu "QoS and/or fair queueing" config NET_SCHED bool "QoS and/or fair queueing" ---help--- When the kernel has several packets to send out over a network device, it has to decide which ones to send first, which ones to delay, and which ones to drop. This is the job of the packet scheduler, and several different algorithms for how to do this "fairly" have been proposed. If you say N here, you will get the standard packet scheduler, which is a FIFO (first come, first served). If you say Y here, you will be able to choose from among several alternative algorithms which can then be attached to different network devices. This is useful for example if some of your network devices are real time devices that need a certain minimum data flow rate, or if you need to limit the maximum data flow rate for traffic which matches specified criteria. This code is considered to be experimental. To administer these schedulers, you'll need the user-level utilities from the package iproute2+tc at . That package also contains some documentation; for more, check out . This Quality of Service (QoS) support will enable you to use Differentiated Services (diffserv) and Resource Reservation Protocol (RSVP) on your Linux router if you also say Y to "QoS support", "Packet classifier API" and to some classifiers below. Documentation and software is at . If you say Y here and to "/proc file system" below, you will be able to read status information about packet schedulers from the file /proc/net/psched. The available schedulers are listed in the following questions; you can say Y to as many as you like. If unsure, say N now. source "net/sched/Kconfig" endmenu menu "Network testing" config NET_PKTGEN tristate "Packet Generator (USE WITH CAUTION)" depends on PROC_FS ---help--- This module will inject preconfigured packets, at a configurable rate, out of a given interface. It is used for network interface stress testing and performance analysis. If you don't understand what was just said, you don't need it: say N. Documentation on how to use the packet generaor can be found at . To compile this code as a module, choose M here: the module will be called pktgen. endmenu endmenu config NETPOLL def_bool NETCONSOLE config NETPOLL_RX bool "Netpoll support for trapping incoming packets" default n depends on NETPOLL config NETPOLL_TRAP bool "Netpoll traffic trapping" default n depends on NETPOLL config NET_POLL_CONTROLLER def_bool NETPOLL source "net/ax25/Kconfig" source "net/irda/Kconfig" source "net/bluetooth/Kconfig" source "drivers/net/Kconfig" endmenu