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/>. For most people, it's safe to say N.
14 config IP_ADVANCED_ROUTER
15 bool "IP: advanced router"
17 If you intend to run your Linux box mostly as a router, i.e. as a
18 computer that forwards and redistributes network packets, say Y; you
19 will then be presented with several options that allow more precise
20 control about the routing process.
22 The answer to this question won't directly affect the kernel:
23 answering N will just cause the configurator to skip all the
24 questions about advanced routing.
26 Note that your box can only act as a router if you enable IP
27 forwarding in your kernel; you can do that by saying Y to "/proc
28 file system support" and "Sysctl support" below and executing the
31 echo "1" > /proc/sys/net/ipv4/ip_forward
33 at boot time after the /proc file system has been mounted.
35 If you turn on IP forwarding, you should consider the rp_filter, which
36 automatically rejects incoming packets if the routing table entry
37 for their source address doesn't match the network interface they're
38 arriving on. This has security advantages because it prevents the
39 so-called IP spoofing, however it can pose problems if you use
40 asymmetric routing (packets from you to a host take a different path
41 than packets from that host to you) or if you operate a non-routing
42 host which has several IP addresses on different interfaces. To turn
45 echo 1 > /proc/sys/net/ipv4/conf/<device>/rp_filter
47 echo 1 > /proc/sys/net/ipv4/conf/all/rp_filter
49 Note that some distributions enable it in startup scripts.
50 For details about rp_filter strict and loose mode read
51 <file:Documentation/networking/ip-sysctl.txt>.
53 If unsure, say N here.
55 config IP_FIB_TRIE_STATS
56 bool "FIB TRIE statistics"
57 depends on IP_ADVANCED_ROUTER
59 Keep track of statistics on structure of FIB TRIE table.
60 Useful for testing and measuring TRIE performance.
62 config IP_MULTIPLE_TABLES
63 bool "IP: policy routing"
64 depends on IP_ADVANCED_ROUTER
67 Normally, a router decides what to do with a received packet based
68 solely on the packet's final destination address. If you say Y here,
69 the Linux router will also be able to take the packet's source
70 address into account. Furthermore, the TOS (Type-Of-Service) field
71 of the packet can be used for routing decisions as well.
73 If you are interested in this, please see the preliminary
74 documentation at <http://www.compendium.com.ar/policy-routing.txt>
75 and <ftp://post.tepkom.ru/pub/vol2/Linux/docs/advanced-routing.tex>.
76 You will need supporting software from
77 <ftp://ftp.tux.org/pub/net/ip-routing/>.
81 config IP_ROUTE_MULTIPATH
82 bool "IP: equal cost multipath"
83 depends on IP_ADVANCED_ROUTER
85 Normally, the routing tables specify a single action to be taken in
86 a deterministic manner for a given packet. If you say Y here
87 however, it becomes possible to attach several actions to a packet
88 pattern, in effect specifying several alternative paths to travel
89 for those packets. The router considers all these paths to be of
90 equal "cost" and chooses one of them in a non-deterministic fashion
91 if a matching packet arrives.
93 config IP_ROUTE_VERBOSE
94 bool "IP: verbose route monitoring"
95 depends on IP_ADVANCED_ROUTER
97 If you say Y here, which is recommended, then the kernel will print
98 verbose messages regarding the routing, for example warnings about
99 received packets which look strange and could be evidence of an
100 attack or a misconfigured system somewhere. The information is
101 handled by the klogd daemon which is responsible for kernel messages
104 config IP_ROUTE_CLASSID
108 bool "IP: kernel level autoconfiguration"
110 This enables automatic configuration of IP addresses of devices and
111 of the routing table during kernel boot, based on either information
112 supplied on the kernel command line or by BOOTP or RARP protocols.
113 You need to say Y only for diskless machines requiring network
114 access to boot (in which case you want to say Y to "Root file system
115 on NFS" as well), because all other machines configure the network
116 in their startup scripts.
119 bool "IP: DHCP support"
122 If you want your Linux box to mount its whole root file system (the
123 one containing the directory /) from some other computer over the
124 net via NFS and you want the IP address of your computer to be
125 discovered automatically at boot time using the DHCP protocol (a
126 special protocol designed for doing this job), say Y here. In case
127 the boot ROM of your network card was designed for booting Linux and
128 does DHCP itself, providing all necessary information on the kernel
129 command line, you can say N here.
131 If unsure, say Y. Note that if you want to use DHCP, a DHCP server
132 must be operating on your network. Read
133 <file:Documentation/filesystems/nfs/nfsroot.txt> for details.
136 bool "IP: BOOTP support"
139 If you want your Linux box to mount its whole root file system (the
140 one containing the directory /) from some other computer over the
141 net via NFS and you want the IP address of your computer to be
142 discovered automatically at boot time using the BOOTP protocol (a
143 special protocol designed for doing this job), say Y here. In case
144 the boot ROM of your network card was designed for booting Linux and
145 does BOOTP itself, providing all necessary information on the kernel
146 command line, you can say N here. If unsure, say Y. Note that if you
147 want to use BOOTP, a BOOTP server must be operating on your network.
148 Read <file:Documentation/filesystems/nfs/nfsroot.txt> for details.
151 bool "IP: RARP support"
154 If you want your Linux box to mount its whole root file system (the
155 one containing the directory /) from some other computer over the
156 net via NFS and you want the IP address of your computer to be
157 discovered automatically at boot time using the RARP protocol (an
158 older protocol which is being obsoleted by BOOTP and DHCP), say Y
159 here. Note that if you want to use RARP, a RARP server must be
160 operating on your network. Read
161 <file:Documentation/filesystems/nfs/nfsroot.txt> for details.
164 tristate "IP: tunneling"
168 Tunneling means encapsulating data of one protocol type within
169 another protocol and sending it over a channel that understands the
170 encapsulating protocol. This particular tunneling driver implements
171 encapsulation of IP within IP, which sounds kind of pointless, but
172 can be useful if you want to make your (or some other) machine
173 appear on a different network than it physically is, or to use
174 mobile-IP facilities (allowing laptops to seamlessly move between
175 networks without changing their IP addresses).
177 Saying Y to this option will produce two modules ( = code which can
178 be inserted in and removed from the running kernel whenever you
179 want). Most people won't need this and can say N.
181 config NET_IPGRE_DEMUX
182 tristate "IP: GRE demultiplexer"
184 This is helper module to demultiplex GRE packets on GRE version field criteria.
185 Required by ip_gre and pptp modules.
193 tristate "IP: GRE tunnels over IP"
194 depends on (IPV6 || IPV6=n) && NET_IPGRE_DEMUX
197 Tunneling means encapsulating data of one protocol type within
198 another protocol and sending it over a channel that understands the
199 encapsulating protocol. This particular tunneling driver implements
200 GRE (Generic Routing Encapsulation) and at this time allows
201 encapsulating of IPv4 or IPv6 over existing IPv4 infrastructure.
202 This driver is useful if the other endpoint is a Cisco router: Cisco
203 likes GRE much better than the other Linux tunneling driver ("IP
204 tunneling" above). In addition, GRE allows multicast redistribution
207 config NET_IPGRE_BROADCAST
208 bool "IP: broadcast GRE over IP"
209 depends on IP_MULTICAST && NET_IPGRE
211 One application of GRE/IP is to construct a broadcast WAN (Wide Area
212 Network), which looks like a normal Ethernet LAN (Local Area
213 Network), but can be distributed all over the Internet. If you want
214 to do that, say Y here and to "IP multicast routing" below.
217 bool "IP: multicast routing"
218 depends on IP_MULTICAST
220 This is used if you want your machine to act as a router for IP
221 packets that have several destination addresses. It is needed on the
222 MBONE, a high bandwidth network on top of the Internet which carries
223 audio and video broadcasts. In order to do that, you would most
224 likely run the program mrouted. If you haven't heard about it, you
227 config IP_MROUTE_MULTIPLE_TABLES
228 bool "IP: multicast policy routing"
229 depends on IP_MROUTE && IP_ADVANCED_ROUTER
232 Normally, a multicast router runs a userspace daemon and decides
233 what to do with a multicast packet based on the source and
234 destination addresses. If you say Y here, the multicast router
235 will also be able to take interfaces and packet marks into
236 account and run multiple instances of userspace daemons
237 simultaneously, each one handling a single table.
242 bool "IP: PIM-SM version 1 support"
245 Kernel side support for Sparse Mode PIM (Protocol Independent
246 Multicast) version 1. This multicast routing protocol is used widely
247 because Cisco supports it. You need special software to use it
248 (pimd-v1). Please see <http://netweb.usc.edu/pim/> for more
249 information about PIM.
251 Say Y if you want to use PIM-SM v1. Note that you can say N here if
252 you just want to use Dense Mode PIM.
255 bool "IP: PIM-SM version 2 support"
258 Kernel side support for Sparse Mode PIM version 2. In order to use
259 this, you need an experimental routing daemon supporting it (pimd or
260 gated-5). This routing protocol is not used widely, so say N unless
261 you want to play with it.
264 bool "IP: TCP syncookie support"
266 Normal TCP/IP networking is open to an attack known as "SYN
267 flooding". This denial-of-service attack prevents legitimate remote
268 users from being able to connect to your computer during an ongoing
269 attack and requires very little work from the attacker, who can
270 operate from anywhere on the Internet.
272 SYN cookies provide protection against this type of attack. If you
273 say Y here, the TCP/IP stack will use a cryptographic challenge
274 protocol known as "SYN cookies" to enable legitimate users to
275 continue to connect, even when your machine is under attack. There
276 is no need for the legitimate users to change their TCP/IP software;
277 SYN cookies work transparently to them. For technical information
278 about SYN cookies, check out <http://cr.yp.to/syncookies.html>.
280 If you are SYN flooded, the source address reported by the kernel is
281 likely to have been forged by the attacker; it is only reported as
282 an aid in tracing the packets to their actual source and should not
283 be taken as absolute truth.
285 SYN cookies may prevent correct error reporting on clients when the
286 server is really overloaded. If this happens frequently better turn
289 If you say Y here, you can disable SYN cookies at run time by
290 saying Y to "/proc file system support" and
291 "Sysctl support" below and executing the command
293 echo 0 > /proc/sys/net/ipv4/tcp_syncookies
295 after the /proc file system has been mounted.
300 tristate "Virtual (secure) IP: tunneling"
301 depends on IPV6 || IPV6=n
304 depends on INET_XFRM_MODE_TUNNEL
306 Tunneling means encapsulating data of one protocol type within
307 another protocol and sending it over a channel that understands the
308 encapsulating protocol. This can be used with xfrm mode tunnel to give
309 the notion of a secure tunnel for IPSEC and then use routing protocol
312 config NET_UDP_TUNNEL
318 tristate "IP: Foo (IP protocols) over UDP"
320 select NET_UDP_TUNNEL
322 Foo over UDP allows any IP protocol to be directly encapsulated
323 over UDP include tunnels (IPIP, GRE, SIT). By encapsulating in UDP
324 network mechanisms and optimizations for UDP (such as ECMP
325 and RSS) can be leveraged to provide better service.
327 config NET_FOU_IP_TUNNELS
328 bool "IP: FOU encapsulation of IP tunnels"
329 depends on NET_IPIP || NET_IPGRE || IPV6_SIT
332 Allow configuration of FOU or GUE encapsulation for IP tunnels.
333 When this option is enabled IP tunnels can be configured to use
334 FOU or GUE encapsulation.
337 tristate "IP: AH transformation"
344 Support for IPsec AH.
349 tristate "IP: ESP transformation"
352 select CRYPTO_AUTHENC
358 select CRYPTO_ECHAINIV
360 Support for IPsec ESP.
365 tristate "IP: IPComp transformation"
366 select INET_XFRM_TUNNEL
369 Support for IP Payload Compression Protocol (IPComp) (RFC3173),
370 typically needed for IPsec.
374 config INET_XFRM_TUNNEL
383 config INET_XFRM_MODE_TRANSPORT
384 tristate "IP: IPsec transport mode"
388 Support for IPsec transport mode.
392 config INET_XFRM_MODE_TUNNEL
393 tristate "IP: IPsec tunnel mode"
397 Support for IPsec tunnel mode.
401 config INET_XFRM_MODE_BEET
402 tristate "IP: IPsec BEET mode"
406 Support for IPsec BEET mode.
411 tristate "Large Receive Offload (ipv4/tcp)"
414 Support for Large Receive Offload (ipv4/tcp).
419 tristate "INET: socket monitoring interface"
422 Support for INET (TCP, DCCP, etc) socket monitoring interface used by
423 native Linux tools such as ss. ss is included in iproute2, currently
426 http://www.linuxfoundation.org/collaborate/workgroups/networking/iproute2
432 def_tristate INET_DIAG
435 tristate "UDP: socket monitoring interface"
436 depends on INET_DIAG && (IPV6 || IPV6=n)
439 Support for UDP socket monitoring interface used by the ss tool.
442 menuconfig TCP_CONG_ADVANCED
443 bool "TCP: advanced congestion control"
445 Support for selection of various TCP congestion control
448 Nearly all users can safely say no here, and a safe default
449 selection will be made (CUBIC with new Reno as a fallback).
456 tristate "Binary Increase Congestion (BIC) control"
459 BIC-TCP is a sender-side only change that ensures a linear RTT
460 fairness under large windows while offering both scalability and
461 bounded TCP-friendliness. The protocol combines two schemes
462 called additive increase and binary search increase. When the
463 congestion window is large, additive increase with a large
464 increment ensures linear RTT fairness as well as good
465 scalability. Under small congestion windows, binary search
466 increase provides TCP friendliness.
467 See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/
469 config TCP_CONG_CUBIC
473 This is version 2.0 of BIC-TCP which uses a cubic growth function
474 among other techniques.
475 See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/cubic-paper.pdf
477 config TCP_CONG_WESTWOOD
478 tristate "TCP Westwood+"
481 TCP Westwood+ is a sender-side only modification of the TCP Reno
482 protocol stack that optimizes the performance of TCP congestion
483 control. It is based on end-to-end bandwidth estimation to set
484 congestion window and slow start threshold after a congestion
485 episode. Using this estimation, TCP Westwood+ adaptively sets a
486 slow start threshold and a congestion window which takes into
487 account the bandwidth used at the time congestion is experienced.
488 TCP Westwood+ significantly increases fairness wrt TCP Reno in
489 wired networks and throughput over wireless links.
495 H-TCP is a send-side only modifications of the TCP Reno
496 protocol stack that optimizes the performance of TCP
497 congestion control for high speed network links. It uses a
498 modeswitch to change the alpha and beta parameters of TCP Reno
499 based on network conditions and in a way so as to be fair with
500 other Reno and H-TCP flows.
502 config TCP_CONG_HSTCP
503 tristate "High Speed TCP"
506 Sally Floyd's High Speed TCP (RFC 3649) congestion control.
507 A modification to TCP's congestion control mechanism for use
508 with large congestion windows. A table indicates how much to
509 increase the congestion window by when an ACK is received.
510 For more detail see http://www.icir.org/floyd/hstcp.html
512 config TCP_CONG_HYBLA
513 tristate "TCP-Hybla congestion control algorithm"
516 TCP-Hybla is a sender-side only change that eliminates penalization of
517 long-RTT, large-bandwidth connections, like when satellite legs are
518 involved, especially when sharing a common bottleneck with normal
519 terrestrial connections.
521 config TCP_CONG_VEGAS
525 TCP Vegas is a sender-side only change to TCP that anticipates
526 the onset of congestion by estimating the bandwidth. TCP Vegas
527 adjusts the sending rate by modifying the congestion
528 window. TCP Vegas should provide less packet loss, but it is
529 not as aggressive as TCP Reno.
531 config TCP_CONG_SCALABLE
532 tristate "Scalable TCP"
535 Scalable TCP is a sender-side only change to TCP which uses a
536 MIMD congestion control algorithm which has some nice scaling
537 properties, though is known to have fairness issues.
538 See http://www.deneholme.net/tom/scalable/
541 tristate "TCP Low Priority"
544 TCP Low Priority (TCP-LP), a distributed algorithm whose goal is
545 to utilize only the excess network bandwidth as compared to the
546 ``fair share`` of bandwidth as targeted by TCP.
547 See http://www-ece.rice.edu/networks/TCP-LP/
553 TCP Veno is a sender-side only enhancement of TCP to obtain better
554 throughput over wireless networks. TCP Veno makes use of state
555 distinguishing to circumvent the difficult judgment of the packet loss
556 type. TCP Veno cuts down less congestion window in response to random
558 See <http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1177186>
562 select TCP_CONG_VEGAS
565 YeAH-TCP is a sender-side high-speed enabled TCP congestion control
566 algorithm, which uses a mixed loss/delay approach to compute the
567 congestion window. It's design goals target high efficiency,
568 internal, RTT and Reno fairness, resilience to link loss while
569 keeping network elements load as low as possible.
571 For further details look here:
572 http://wil.cs.caltech.edu/pfldnet2007/paper/YeAH_TCP.pdf
574 config TCP_CONG_ILLINOIS
575 tristate "TCP Illinois"
578 TCP-Illinois is a sender-side modification of TCP Reno for
579 high speed long delay links. It uses round-trip-time to
580 adjust the alpha and beta parameters to achieve a higher average
581 throughput and maintain fairness.
583 For further details see:
584 http://www.ews.uiuc.edu/~shaoliu/tcpillinois/index.html
586 config TCP_CONG_DCTCP
587 tristate "DataCenter TCP (DCTCP)"
590 DCTCP leverages Explicit Congestion Notification (ECN) in the network to
591 provide multi-bit feedback to the end hosts. It is designed to provide:
593 - High burst tolerance (incast due to partition/aggregate),
594 - Low latency (short flows, queries),
595 - High throughput (continuous data updates, large file transfers) with
596 commodity, shallow-buffered switches.
598 All switches in the data center network running DCTCP must support
599 ECN marking and be configured for marking when reaching defined switch
600 buffer thresholds. The default ECN marking threshold heuristic for
601 DCTCP on switches is 20 packets (30KB) at 1Gbps, and 65 packets
602 (~100KB) at 10Gbps, but might need further careful tweaking.
604 For further details see:
605 http://simula.stanford.edu/~alizade/Site/DCTCP_files/dctcp-final.pdf
608 tristate "CAIA Delay-Gradient (CDG)"
611 CAIA Delay-Gradient (CDG) is a TCP congestion control that modifies
612 the TCP sender in order to:
614 o Use the delay gradient as a congestion signal.
615 o Back off with an average probability that is independent of the RTT.
616 o Coexist with flows that use loss-based congestion control.
617 o Tolerate packet loss unrelated to congestion.
619 For further details see:
620 D.A. Hayes and G. Armitage. "Revisiting TCP congestion control using
621 delay gradients." In Networking 2011. Preprint: http://goo.gl/No3vdg
624 prompt "Default TCP congestion control"
625 default DEFAULT_CUBIC
627 Select the TCP congestion control that will be used by default
631 bool "Bic" if TCP_CONG_BIC=y
634 bool "Cubic" if TCP_CONG_CUBIC=y
637 bool "Htcp" if TCP_CONG_HTCP=y
640 bool "Hybla" if TCP_CONG_HYBLA=y
643 bool "Vegas" if TCP_CONG_VEGAS=y
646 bool "Veno" if TCP_CONG_VENO=y
648 config DEFAULT_WESTWOOD
649 bool "Westwood" if TCP_CONG_WESTWOOD=y
652 bool "DCTCP" if TCP_CONG_DCTCP=y
655 bool "CDG" if TCP_CONG_CDG=y
663 config TCP_CONG_CUBIC
665 depends on !TCP_CONG_ADVANCED
668 config DEFAULT_TCP_CONG
670 default "bic" if DEFAULT_BIC
671 default "cubic" if DEFAULT_CUBIC
672 default "htcp" if DEFAULT_HTCP
673 default "hybla" if DEFAULT_HYBLA
674 default "vegas" if DEFAULT_VEGAS
675 default "westwood" if DEFAULT_WESTWOOD
676 default "veno" if DEFAULT_VENO
677 default "reno" if DEFAULT_RENO
678 default "dctcp" if DEFAULT_DCTCP
679 default "cdg" if DEFAULT_CDG
683 bool "TCP: MD5 Signature Option support (RFC2385)"
687 RFC2385 specifies a method of giving MD5 protection to TCP sessions.
688 Its main (only?) use is to protect BGP sessions between core routers