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.
192 tristate "IP: GRE tunnels over IP"
193 depends on (IPV6 || IPV6=n) && NET_IPGRE_DEMUX
196 Tunneling means encapsulating data of one protocol type within
197 another protocol and sending it over a channel that understands the
198 encapsulating protocol. This particular tunneling driver implements
199 GRE (Generic Routing Encapsulation) and at this time allows
200 encapsulating of IPv4 or IPv6 over existing IPv4 infrastructure.
201 This driver is useful if the other endpoint is a Cisco router: Cisco
202 likes GRE much better than the other Linux tunneling driver ("IP
203 tunneling" above). In addition, GRE allows multicast redistribution
206 config NET_IPGRE_BROADCAST
207 bool "IP: broadcast GRE over IP"
208 depends on IP_MULTICAST && NET_IPGRE
210 One application of GRE/IP is to construct a broadcast WAN (Wide Area
211 Network), which looks like a normal Ethernet LAN (Local Area
212 Network), but can be distributed all over the Internet. If you want
213 to do that, say Y here and to "IP multicast routing" below.
216 bool "IP: multicast routing"
217 depends on IP_MULTICAST
219 This is used if you want your machine to act as a router for IP
220 packets that have several destination addresses. It is needed on the
221 MBONE, a high bandwidth network on top of the Internet which carries
222 audio and video broadcasts. In order to do that, you would most
223 likely run the program mrouted. If you haven't heard about it, you
226 config IP_MROUTE_MULTIPLE_TABLES
227 bool "IP: multicast policy routing"
228 depends on IP_MROUTE && IP_ADVANCED_ROUTER
231 Normally, a multicast router runs a userspace daemon and decides
232 what to do with a multicast packet based on the source and
233 destination addresses. If you say Y here, the multicast router
234 will also be able to take interfaces and packet marks into
235 account and run multiple instances of userspace daemons
236 simultaneously, each one handling a single table.
241 bool "IP: PIM-SM version 1 support"
244 Kernel side support for Sparse Mode PIM (Protocol Independent
245 Multicast) version 1. This multicast routing protocol is used widely
246 because Cisco supports it. You need special software to use it
247 (pimd-v1). Please see <http://netweb.usc.edu/pim/> for more
248 information about PIM.
250 Say Y if you want to use PIM-SM v1. Note that you can say N here if
251 you just want to use Dense Mode PIM.
254 bool "IP: PIM-SM version 2 support"
257 Kernel side support for Sparse Mode PIM version 2. In order to use
258 this, you need an experimental routing daemon supporting it (pimd or
259 gated-5). This routing protocol is not used widely, so say N unless
260 you want to play with it.
263 bool "IP: TCP syncookie support"
265 Normal TCP/IP networking is open to an attack known as "SYN
266 flooding". This denial-of-service attack prevents legitimate remote
267 users from being able to connect to your computer during an ongoing
268 attack and requires very little work from the attacker, who can
269 operate from anywhere on the Internet.
271 SYN cookies provide protection against this type of attack. If you
272 say Y here, the TCP/IP stack will use a cryptographic challenge
273 protocol known as "SYN cookies" to enable legitimate users to
274 continue to connect, even when your machine is under attack. There
275 is no need for the legitimate users to change their TCP/IP software;
276 SYN cookies work transparently to them. For technical information
277 about SYN cookies, check out <http://cr.yp.to/syncookies.html>.
279 If you are SYN flooded, the source address reported by the kernel is
280 likely to have been forged by the attacker; it is only reported as
281 an aid in tracing the packets to their actual source and should not
282 be taken as absolute truth.
284 SYN cookies may prevent correct error reporting on clients when the
285 server is really overloaded. If this happens frequently better turn
288 If you say Y here, you can disable SYN cookies at run time by
289 saying Y to "/proc file system support" and
290 "Sysctl support" below and executing the command
292 echo 0 > /proc/sys/net/ipv4/tcp_syncookies
294 after the /proc file system has been mounted.
299 tristate "Virtual (secure) IP: tunneling"
302 depends on INET_XFRM_MODE_TUNNEL
304 Tunneling means encapsulating data of one protocol type within
305 another protocol and sending it over a channel that understands the
306 encapsulating protocol. This can be used with xfrm mode tunnel to give
307 the notion of a secure tunnel for IPSEC and then use routing protocol
310 config NET_UDP_TUNNEL
316 tristate "IP: Foo (IP protocols) over UDP"
318 select NET_UDP_TUNNEL
320 Foo over UDP allows any IP protocol to be directly encapsulated
321 over UDP include tunnels (IPIP, GRE, SIT). By encapsulating in UDP
322 network mechanisms and optimizations for UDP (such as ECMP
323 and RSS) can be leveraged to provide better service.
326 tristate "Generic Network Virtualization Encapsulation (Geneve)"
328 select NET_UDP_TUNNEL
330 This allows one to create Geneve virtual interfaces that provide
331 Layer 2 Networks over Layer 3 Networks. Geneve is often used
332 to tunnel virtual network infrastructure in virtualized environments.
333 For more information see:
334 http://tools.ietf.org/html/draft-gross-geneve-01
336 To compile this driver as a module, choose M here: the module
340 tristate "IP: AH transformation"
347 Support for IPsec AH.
352 tristate "IP: ESP transformation"
355 select CRYPTO_AUTHENC
362 Support for IPsec ESP.
367 tristate "IP: IPComp transformation"
368 select INET_XFRM_TUNNEL
371 Support for IP Payload Compression Protocol (IPComp) (RFC3173),
372 typically needed for IPsec.
376 config INET_XFRM_TUNNEL
385 config INET_XFRM_MODE_TRANSPORT
386 tristate "IP: IPsec transport mode"
390 Support for IPsec transport mode.
394 config INET_XFRM_MODE_TUNNEL
395 tristate "IP: IPsec tunnel mode"
399 Support for IPsec tunnel mode.
403 config INET_XFRM_MODE_BEET
404 tristate "IP: IPsec BEET mode"
408 Support for IPsec BEET mode.
413 tristate "Large Receive Offload (ipv4/tcp)"
416 Support for Large Receive Offload (ipv4/tcp).
421 tristate "INET: socket monitoring interface"
424 Support for INET (TCP, DCCP, etc) socket monitoring interface used by
425 native Linux tools such as ss. ss is included in iproute2, currently
428 http://www.linuxfoundation.org/collaborate/workgroups/networking/iproute2
434 def_tristate INET_DIAG
437 tristate "UDP: socket monitoring interface"
438 depends on INET_DIAG && (IPV6 || IPV6=n)
441 Support for UDP socket monitoring interface used by the ss tool.
444 menuconfig TCP_CONG_ADVANCED
445 bool "TCP: advanced congestion control"
447 Support for selection of various TCP congestion control
450 Nearly all users can safely say no here, and a safe default
451 selection will be made (CUBIC with new Reno as a fallback).
458 tristate "Binary Increase Congestion (BIC) control"
461 BIC-TCP is a sender-side only change that ensures a linear RTT
462 fairness under large windows while offering both scalability and
463 bounded TCP-friendliness. The protocol combines two schemes
464 called additive increase and binary search increase. When the
465 congestion window is large, additive increase with a large
466 increment ensures linear RTT fairness as well as good
467 scalability. Under small congestion windows, binary search
468 increase provides TCP friendliness.
469 See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/
471 config TCP_CONG_CUBIC
475 This is version 2.0 of BIC-TCP which uses a cubic growth function
476 among other techniques.
477 See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/cubic-paper.pdf
479 config TCP_CONG_WESTWOOD
480 tristate "TCP Westwood+"
483 TCP Westwood+ is a sender-side only modification of the TCP Reno
484 protocol stack that optimizes the performance of TCP congestion
485 control. It is based on end-to-end bandwidth estimation to set
486 congestion window and slow start threshold after a congestion
487 episode. Using this estimation, TCP Westwood+ adaptively sets a
488 slow start threshold and a congestion window which takes into
489 account the bandwidth used at the time congestion is experienced.
490 TCP Westwood+ significantly increases fairness wrt TCP Reno in
491 wired networks and throughput over wireless links.
497 H-TCP is a send-side only modifications of the TCP Reno
498 protocol stack that optimizes the performance of TCP
499 congestion control for high speed network links. It uses a
500 modeswitch to change the alpha and beta parameters of TCP Reno
501 based on network conditions and in a way so as to be fair with
502 other Reno and H-TCP flows.
504 config TCP_CONG_HSTCP
505 tristate "High Speed TCP"
508 Sally Floyd's High Speed TCP (RFC 3649) congestion control.
509 A modification to TCP's congestion control mechanism for use
510 with large congestion windows. A table indicates how much to
511 increase the congestion window by when an ACK is received.
512 For more detail see http://www.icir.org/floyd/hstcp.html
514 config TCP_CONG_HYBLA
515 tristate "TCP-Hybla congestion control algorithm"
518 TCP-Hybla is a sender-side only change that eliminates penalization of
519 long-RTT, large-bandwidth connections, like when satellite legs are
520 involved, especially when sharing a common bottleneck with normal
521 terrestrial connections.
523 config TCP_CONG_VEGAS
527 TCP Vegas is a sender-side only change to TCP that anticipates
528 the onset of congestion by estimating the bandwidth. TCP Vegas
529 adjusts the sending rate by modifying the congestion
530 window. TCP Vegas should provide less packet loss, but it is
531 not as aggressive as TCP Reno.
533 config TCP_CONG_SCALABLE
534 tristate "Scalable TCP"
537 Scalable TCP is a sender-side only change to TCP which uses a
538 MIMD congestion control algorithm which has some nice scaling
539 properties, though is known to have fairness issues.
540 See http://www.deneholme.net/tom/scalable/
543 tristate "TCP Low Priority"
546 TCP Low Priority (TCP-LP), a distributed algorithm whose goal is
547 to utilize only the excess network bandwidth as compared to the
548 ``fair share`` of bandwidth as targeted by TCP.
549 See http://www-ece.rice.edu/networks/TCP-LP/
555 TCP Veno is a sender-side only enhancement of TCP to obtain better
556 throughput over wireless networks. TCP Veno makes use of state
557 distinguishing to circumvent the difficult judgment of the packet loss
558 type. TCP Veno cuts down less congestion window in response to random
560 See <http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1177186>
564 select TCP_CONG_VEGAS
567 YeAH-TCP is a sender-side high-speed enabled TCP congestion control
568 algorithm, which uses a mixed loss/delay approach to compute the
569 congestion window. It's design goals target high efficiency,
570 internal, RTT and Reno fairness, resilience to link loss while
571 keeping network elements load as low as possible.
573 For further details look here:
574 http://wil.cs.caltech.edu/pfldnet2007/paper/YeAH_TCP.pdf
576 config TCP_CONG_ILLINOIS
577 tristate "TCP Illinois"
580 TCP-Illinois is a sender-side modification of TCP Reno for
581 high speed long delay links. It uses round-trip-time to
582 adjust the alpha and beta parameters to achieve a higher average
583 throughput and maintain fairness.
585 For further details see:
586 http://www.ews.uiuc.edu/~shaoliu/tcpillinois/index.html
588 config TCP_CONG_DCTCP
589 tristate "DataCenter TCP (DCTCP)"
592 DCTCP leverages Explicit Congestion Notification (ECN) in the network to
593 provide multi-bit feedback to the end hosts. It is designed to provide:
595 - High burst tolerance (incast due to partition/aggregate),
596 - Low latency (short flows, queries),
597 - High throughput (continuous data updates, large file transfers) with
598 commodity, shallow-buffered switches.
600 All switches in the data center network running DCTCP must support
601 ECN marking and be configured for marking when reaching defined switch
602 buffer thresholds. The default ECN marking threshold heuristic for
603 DCTCP on switches is 20 packets (30KB) at 1Gbps, and 65 packets
604 (~100KB) at 10Gbps, but might need further careful tweaking.
606 For further details see:
607 http://simula.stanford.edu/~alizade/Site/DCTCP_files/dctcp-final.pdf
610 prompt "Default TCP congestion control"
611 default DEFAULT_CUBIC
613 Select the TCP congestion control that will be used by default
617 bool "Bic" if TCP_CONG_BIC=y
620 bool "Cubic" if TCP_CONG_CUBIC=y
623 bool "Htcp" if TCP_CONG_HTCP=y
626 bool "Hybla" if TCP_CONG_HYBLA=y
629 bool "Vegas" if TCP_CONG_VEGAS=y
632 bool "Veno" if TCP_CONG_VENO=y
634 config DEFAULT_WESTWOOD
635 bool "Westwood" if TCP_CONG_WESTWOOD=y
638 bool "DCTCP" if TCP_CONG_DCTCP=y
646 config TCP_CONG_CUBIC
648 depends on !TCP_CONG_ADVANCED
651 config DEFAULT_TCP_CONG
653 default "bic" if DEFAULT_BIC
654 default "cubic" if DEFAULT_CUBIC
655 default "htcp" if DEFAULT_HTCP
656 default "hybla" if DEFAULT_HYBLA
657 default "vegas" if DEFAULT_VEGAS
658 default "westwood" if DEFAULT_WESTWOOD
659 default "veno" if DEFAULT_VENO
660 default "reno" if DEFAULT_RENO
661 default "dctcp" if DEFAULT_DCTCP
665 bool "TCP: MD5 Signature Option support (RFC2385)"
669 RFC2385 specifies a method of giving MD5 protection to TCP sessions.
670 Its main (only?) use is to protect BGP sessions between core routers