5 bool "IP: multicasting"
7 This is code for addressing several networked computers at once,
8 enlarging your kernel by about 2 KB. You need multicasting if you
9 intend to participate in the MBONE, a high bandwidth network on top
10 of the Internet which carries audio and video broadcasts. More
11 information about the MBONE is on the WWW at
12 <http://www.savetz.com/mbone/>. Information about the multicast
13 capabilities of the various network cards is contained in
14 <file:Documentation/networking/multicast.txt>. For most people, it's
17 config IP_ADVANCED_ROUTER
18 bool "IP: advanced router"
20 If you intend to run your Linux box mostly as a router, i.e. as a
21 computer that forwards and redistributes network packets, say Y; you
22 will then be presented with several options that allow more precise
23 control about the routing process.
25 The answer to this question won't directly affect the kernel:
26 answering N will just cause the configurator to skip all the
27 questions about advanced routing.
29 Note that your box can only act as a router if you enable IP
30 forwarding in your kernel; you can do that by saying Y to "/proc
31 file system support" and "Sysctl support" below and executing the
34 echo "1" > /proc/sys/net/ipv4/ip_forward
36 at boot time after the /proc file system has been mounted.
38 If you turn on IP forwarding, you will also get the rp_filter, which
39 automatically rejects incoming packets if the routing table entry
40 for their source address doesn't match the network interface they're
41 arriving on. This has security advantages because it prevents the
42 so-called IP spoofing, however it can pose problems if you use
43 asymmetric routing (packets from you to a host take a different path
44 than packets from that host to you) or if you operate a non-routing
45 host which has several IP addresses on different interfaces. To turn
48 echo 1 > /proc/sys/net/ipv4/conf/<device>/rp_filter
50 echo 1 > /proc/sys/net/ipv4/conf/all/rp_filter
52 If unsure, say N here.
55 prompt "Choose IP: FIB lookup algorithm (choose FIB_HASH if unsure)"
56 depends on IP_ADVANCED_ROUTER
57 default ASK_IP_FIB_HASH
59 config ASK_IP_FIB_HASH
62 Current FIB is very proven and good enough for most users.
67 Use new experimental LC-trie as FIB lookup algorithm.
68 This improves lookup performance if you have a large
71 LC-trie is a longest matching prefix lookup algorithm which
72 performs better than FIB_HASH for large routing tables.
73 But, it consumes more memory and is more complex.
75 LC-trie is described in:
77 IP-address lookup using LC-tries. Stefan Nilsson and Gunnar Karlsson
78 IEEE Journal on Selected Areas in Communications, 17(6):1083-1092, June 1999
79 An experimental study of compression methods for dynamic tries
80 Stefan Nilsson and Matti Tikkanen. Algorithmica, 33(1):19-33, 2002.
81 http://www.nada.kth.se/~snilsson/public/papers/dyntrie2/
86 def_bool ASK_IP_FIB_HASH || !IP_ADVANCED_ROUTER
88 config IP_FIB_TRIE_STATS
89 bool "FIB TRIE statistics"
90 depends on IP_FIB_TRIE
92 Keep track of statistics on structure of FIB TRIE table.
93 Useful for testing and measuring TRIE performance.
95 config IP_MULTIPLE_TABLES
96 bool "IP: policy routing"
97 depends on IP_ADVANCED_ROUTER
100 Normally, a router decides what to do with a received packet based
101 solely on the packet's final destination address. If you say Y here,
102 the Linux router will also be able to take the packet's source
103 address into account. Furthermore, the TOS (Type-Of-Service) field
104 of the packet can be used for routing decisions as well.
106 If you are interested in this, please see the preliminary
107 documentation at <http://www.compendium.com.ar/policy-routing.txt>
108 and <ftp://post.tepkom.ru/pub/vol2/Linux/docs/advanced-routing.tex>.
109 You will need supporting software from
110 <ftp://ftp.tux.org/pub/net/ip-routing/>.
114 config IP_ROUTE_MULTIPATH
115 bool "IP: equal cost multipath"
116 depends on IP_ADVANCED_ROUTER
118 Normally, the routing tables specify a single action to be taken in
119 a deterministic manner for a given packet. If you say Y here
120 however, it becomes possible to attach several actions to a packet
121 pattern, in effect specifying several alternative paths to travel
122 for those packets. The router considers all these paths to be of
123 equal "cost" and chooses one of them in a non-deterministic fashion
124 if a matching packet arrives.
126 config IP_ROUTE_VERBOSE
127 bool "IP: verbose route monitoring"
128 depends on IP_ADVANCED_ROUTER
130 If you say Y here, which is recommended, then the kernel will print
131 verbose messages regarding the routing, for example warnings about
132 received packets which look strange and could be evidence of an
133 attack or a misconfigured system somewhere. The information is
134 handled by the klogd daemon which is responsible for kernel messages
138 bool "IP: kernel level autoconfiguration"
140 This enables automatic configuration of IP addresses of devices and
141 of the routing table during kernel boot, based on either information
142 supplied on the kernel command line or by BOOTP or RARP protocols.
143 You need to say Y only for diskless machines requiring network
144 access to boot (in which case you want to say Y to "Root file system
145 on NFS" as well), because all other machines configure the network
146 in their startup scripts.
149 bool "IP: DHCP support"
152 If you want your Linux box to mount its whole root file system (the
153 one containing the directory /) from some other computer over the
154 net via NFS and you want the IP address of your computer to be
155 discovered automatically at boot time using the DHCP protocol (a
156 special protocol designed for doing this job), say Y here. In case
157 the boot ROM of your network card was designed for booting Linux and
158 does DHCP itself, providing all necessary information on the kernel
159 command line, you can say N here.
161 If unsure, say Y. Note that if you want to use DHCP, a DHCP server
162 must be operating on your network. Read
163 <file:Documentation/nfsroot.txt> for details.
166 bool "IP: BOOTP support"
169 If you want your Linux box to mount its whole root file system (the
170 one containing the directory /) from some other computer over the
171 net via NFS and you want the IP address of your computer to be
172 discovered automatically at boot time using the BOOTP protocol (a
173 special protocol designed for doing this job), say Y here. In case
174 the boot ROM of your network card was designed for booting Linux and
175 does BOOTP itself, providing all necessary information on the kernel
176 command line, you can say N here. If unsure, say Y. Note that if you
177 want to use BOOTP, a BOOTP server must be operating on your network.
178 Read <file:Documentation/nfsroot.txt> for details.
181 bool "IP: RARP support"
184 If you want your Linux box to mount its whole root file system (the
185 one containing the directory /) from some other computer over the
186 net via NFS and you want the IP address of your computer to be
187 discovered automatically at boot time using the RARP protocol (an
188 older protocol which is being obsoleted by BOOTP and DHCP), say Y
189 here. Note that if you want to use RARP, a RARP server must be
190 operating on your network. Read <file:Documentation/nfsroot.txt> for
194 # bool ' IP: ARP support' CONFIG_IP_PNP_ARP
196 tristate "IP: tunneling"
199 Tunneling means encapsulating data of one protocol type within
200 another protocol and sending it over a channel that understands the
201 encapsulating protocol. This particular tunneling driver implements
202 encapsulation of IP within IP, which sounds kind of pointless, but
203 can be useful if you want to make your (or some other) machine
204 appear on a different network than it physically is, or to use
205 mobile-IP facilities (allowing laptops to seamlessly move between
206 networks without changing their IP addresses).
208 Saying Y to this option will produce two modules ( = code which can
209 be inserted in and removed from the running kernel whenever you
210 want). Most people won't need this and can say N.
213 tristate "IP: GRE tunnels over IP"
215 Tunneling means encapsulating data of one protocol type within
216 another protocol and sending it over a channel that understands the
217 encapsulating protocol. This particular tunneling driver implements
218 GRE (Generic Routing Encapsulation) and at this time allows
219 encapsulating of IPv4 or IPv6 over existing IPv4 infrastructure.
220 This driver is useful if the other endpoint is a Cisco router: Cisco
221 likes GRE much better than the other Linux tunneling driver ("IP
222 tunneling" above). In addition, GRE allows multicast redistribution
225 config NET_IPGRE_BROADCAST
226 bool "IP: broadcast GRE over IP"
227 depends on IP_MULTICAST && NET_IPGRE
229 One application of GRE/IP is to construct a broadcast WAN (Wide Area
230 Network), which looks like a normal Ethernet LAN (Local Area
231 Network), but can be distributed all over the Internet. If you want
232 to do that, say Y here and to "IP multicast routing" below.
235 bool "IP: multicast routing"
236 depends on IP_MULTICAST
238 This is used if you want your machine to act as a router for IP
239 packets that have several destination addresses. It is needed on the
240 MBONE, a high bandwidth network on top of the Internet which carries
241 audio and video broadcasts. In order to do that, you would most
242 likely run the program mrouted. Information about the multicast
243 capabilities of the various network cards is contained in
244 <file:Documentation/networking/multicast.txt>. If you haven't heard
245 about it, you don't need it.
248 bool "IP: PIM-SM version 1 support"
251 Kernel side support for Sparse Mode PIM (Protocol Independent
252 Multicast) version 1. This multicast routing protocol is used widely
253 because Cisco supports it. You need special software to use it
254 (pimd-v1). Please see <http://netweb.usc.edu/pim/> for more
255 information about PIM.
257 Say Y if you want to use PIM-SM v1. Note that you can say N here if
258 you just want to use Dense Mode PIM.
261 bool "IP: PIM-SM version 2 support"
264 Kernel side support for Sparse Mode PIM version 2. In order to use
265 this, you need an experimental routing daemon supporting it (pimd or
266 gated-5). This routing protocol is not used widely, so say N unless
267 you want to play with it.
270 bool "IP: ARP daemon support (EXPERIMENTAL)"
271 depends on EXPERIMENTAL
273 Normally, the kernel maintains an internal cache which maps IP
274 addresses to hardware addresses on the local network, so that
275 Ethernet/Token Ring/ etc. frames are sent to the proper address on
276 the physical networking layer. For small networks having a few
277 hundred directly connected hosts or less, keeping this address
278 resolution (ARP) cache inside the kernel works well. However,
279 maintaining an internal ARP cache does not work well for very large
280 switched networks, and will use a lot of kernel memory if TCP/IP
281 connections are made to many machines on the network.
283 If you say Y here, the kernel's internal ARP cache will never grow
284 to more than 256 entries (the oldest entries are expired in a LIFO
285 manner) and communication will be attempted with the user space ARP
286 daemon arpd. Arpd then answers the address resolution request either
287 from its own cache or by asking the net.
289 This code is experimental and also obsolete. If you want to use it,
290 you need to find a version of the daemon arpd on the net somewhere,
291 and you should also say Y to "Kernel/User network link driver",
292 below. If unsure, say N.
295 bool "IP: TCP syncookie support (disabled per default)"
297 Normal TCP/IP networking is open to an attack known as "SYN
298 flooding". This denial-of-service attack prevents legitimate remote
299 users from being able to connect to your computer during an ongoing
300 attack and requires very little work from the attacker, who can
301 operate from anywhere on the Internet.
303 SYN cookies provide protection against this type of attack. If you
304 say Y here, the TCP/IP stack will use a cryptographic challenge
305 protocol known as "SYN cookies" to enable legitimate users to
306 continue to connect, even when your machine is under attack. There
307 is no need for the legitimate users to change their TCP/IP software;
308 SYN cookies work transparently to them. For technical information
309 about SYN cookies, check out <http://cr.yp.to/syncookies.html>.
311 If you are SYN flooded, the source address reported by the kernel is
312 likely to have been forged by the attacker; it is only reported as
313 an aid in tracing the packets to their actual source and should not
314 be taken as absolute truth.
316 SYN cookies may prevent correct error reporting on clients when the
317 server is really overloaded. If this happens frequently better turn
320 If you say Y here, note that SYN cookies aren't enabled by default;
321 you can enable them by saying Y to "/proc file system support" and
322 "Sysctl support" below and executing the command
324 echo 1 >/proc/sys/net/ipv4/tcp_syncookies
326 at boot time after the /proc file system has been mounted.
331 tristate "IP: AH transformation"
338 Support for IPsec AH.
343 tristate "IP: ESP transformation"
346 <<<<<<< HEAD:net/ipv4/Kconfig
349 select CRYPTO_AUTHENC
350 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:net/ipv4/Kconfig
357 Support for IPsec ESP.
362 tristate "IP: IPComp transformation"
364 select INET_XFRM_TUNNEL
366 select CRYPTO_DEFLATE
368 Support for IP Payload Compression Protocol (IPComp) (RFC3173),
369 typically needed for IPsec.
373 config INET_XFRM_TUNNEL
382 config INET_XFRM_MODE_TRANSPORT
383 tristate "IP: IPsec transport mode"
387 Support for IPsec transport mode.
391 config INET_XFRM_MODE_TUNNEL
392 tristate "IP: IPsec tunnel mode"
396 Support for IPsec tunnel mode.
400 config INET_XFRM_MODE_BEET
401 tristate "IP: IPsec BEET mode"
405 Support for IPsec BEET mode.
410 tristate "Large Receive Offload (ipv4/tcp)"
413 Support for Large Receive Offload (ipv4/tcp).
418 tristate "INET: socket monitoring interface"
421 Support for INET (TCP, DCCP, etc) socket monitoring interface used by
422 native Linux tools such as ss. ss is included in iproute2, currently
423 downloadable at <http://linux-net.osdl.org/index.php/Iproute2>.
429 def_tristate INET_DIAG
431 menuconfig TCP_CONG_ADVANCED
432 bool "TCP: advanced congestion control"
434 Support for selection of various TCP congestion control
437 Nearly all users can safely say no here, and a safe default
438 selection will be made (CUBIC with new Reno as a fallback).
445 tristate "Binary Increase Congestion (BIC) control"
448 BIC-TCP is a sender-side only change that ensures a linear RTT
449 fairness under large windows while offering both scalability and
450 bounded TCP-friendliness. The protocol combines two schemes
451 called additive increase and binary search increase. When the
452 congestion window is large, additive increase with a large
453 increment ensures linear RTT fairness as well as good
454 scalability. Under small congestion windows, binary search
455 increase provides TCP friendliness.
456 See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/
458 config TCP_CONG_CUBIC
462 This is version 2.0 of BIC-TCP which uses a cubic growth function
463 among other techniques.
464 See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/cubic-paper.pdf
466 config TCP_CONG_WESTWOOD
467 tristate "TCP Westwood+"
470 TCP Westwood+ is a sender-side only modification of the TCP Reno
471 protocol stack that optimizes the performance of TCP congestion
472 control. It is based on end-to-end bandwidth estimation to set
473 congestion window and slow start threshold after a congestion
474 episode. Using this estimation, TCP Westwood+ adaptively sets a
475 slow start threshold and a congestion window which takes into
476 account the bandwidth used at the time congestion is experienced.
477 TCP Westwood+ significantly increases fairness wrt TCP Reno in
478 wired networks and throughput over wireless links.
484 H-TCP is a send-side only modifications of the TCP Reno
485 protocol stack that optimizes the performance of TCP
486 congestion control for high speed network links. It uses a
487 modeswitch to change the alpha and beta parameters of TCP Reno
488 based on network conditions and in a way so as to be fair with
489 other Reno and H-TCP flows.
491 config TCP_CONG_HSTCP
492 tristate "High Speed TCP"
493 depends on EXPERIMENTAL
496 Sally Floyd's High Speed TCP (RFC 3649) congestion control.
497 A modification to TCP's congestion control mechanism for use
498 with large congestion windows. A table indicates how much to
499 increase the congestion window by when an ACK is received.
500 For more detail see http://www.icir.org/floyd/hstcp.html
502 config TCP_CONG_HYBLA
503 tristate "TCP-Hybla congestion control algorithm"
504 depends on EXPERIMENTAL
507 TCP-Hybla is a sender-side only change that eliminates penalization of
508 long-RTT, large-bandwidth connections, like when satellite legs are
509 involved, especially when sharing a common bottleneck with normal
510 terrestrial connections.
512 config TCP_CONG_VEGAS
514 depends on EXPERIMENTAL
517 TCP Vegas is a sender-side only change to TCP that anticipates
518 the onset of congestion by estimating the bandwidth. TCP Vegas
519 adjusts the sending rate by modifying the congestion
520 window. TCP Vegas should provide less packet loss, but it is
521 not as aggressive as TCP Reno.
523 config TCP_CONG_SCALABLE
524 tristate "Scalable TCP"
525 depends on EXPERIMENTAL
528 Scalable TCP is a sender-side only change to TCP which uses a
529 MIMD congestion control algorithm which has some nice scaling
530 properties, though is known to have fairness issues.
531 See http://www.deneholme.net/tom/scalable/
534 tristate "TCP Low Priority"
535 depends on EXPERIMENTAL
538 TCP Low Priority (TCP-LP), a distributed algorithm whose goal is
539 to utilize only the excess network bandwidth as compared to the
540 ``fair share`` of bandwidth as targeted by TCP.
541 See http://www-ece.rice.edu/networks/TCP-LP/
545 depends on EXPERIMENTAL
548 TCP Veno is a sender-side only enhancement of TCP to obtain better
549 throughput over wireless networks. TCP Veno makes use of state
550 distinguishing to circumvent the difficult judgment of the packet loss
551 type. TCP Veno cuts down less congestion window in response to random
553 See http://www.ntu.edu.sg/home5/ZHOU0022/papers/CPFu03a.pdf
557 depends on EXPERIMENTAL
558 select TCP_CONG_VEGAS
561 YeAH-TCP is a sender-side high-speed enabled TCP congestion control
562 algorithm, which uses a mixed loss/delay approach to compute the
563 congestion window. It's design goals target high efficiency,
564 internal, RTT and Reno fairness, resilience to link loss while
565 keeping network elements load as low as possible.
567 For further details look here:
568 http://wil.cs.caltech.edu/pfldnet2007/paper/YeAH_TCP.pdf
570 config TCP_CONG_ILLINOIS
571 tristate "TCP Illinois"
572 depends on EXPERIMENTAL
575 TCP-Illinois is a sender-side modification of TCP Reno for
576 high speed long delay links. It uses round-trip-time to
577 adjust the alpha and beta parameters to achieve a higher average
578 throughput and maintain fairness.
580 For further details see:
581 http://www.ews.uiuc.edu/~shaoliu/tcpillinois/index.html
584 prompt "Default TCP congestion control"
585 default DEFAULT_CUBIC
587 Select the TCP congestion control that will be used by default
591 bool "Bic" if TCP_CONG_BIC=y
594 bool "Cubic" if TCP_CONG_CUBIC=y
597 bool "Htcp" if TCP_CONG_HTCP=y
600 bool "Vegas" if TCP_CONG_VEGAS=y
602 config DEFAULT_WESTWOOD
603 bool "Westwood" if TCP_CONG_WESTWOOD=y
612 config TCP_CONG_CUBIC
614 depends on !TCP_CONG_ADVANCED
617 config DEFAULT_TCP_CONG
619 default "bic" if DEFAULT_BIC
620 default "cubic" if DEFAULT_CUBIC
621 default "htcp" if DEFAULT_HTCP
622 default "vegas" if DEFAULT_VEGAS
623 default "westwood" if DEFAULT_WESTWOOD
624 default "reno" if DEFAULT_RENO
628 bool "TCP: MD5 Signature Option support (RFC2385) (EXPERIMENTAL)"
629 depends on EXPERIMENTAL
633 RFC2385 specifies a method of giving MD5 protection to TCP sessions.
634 Its main (only?) use is to protect BGP sessions between core routers
639 source "net/ipv4/ipvs/Kconfig"