1# 2# IP configuration 3# 4config IP_MULTICAST 5 bool "IP: multicasting" 6 depends on INET 7 help 8 This is code for addressing several networked computers at once, 9 enlarging your kernel by about 2 KB. You need multicasting if you 10 intend to participate in the MBONE, a high bandwidth network on top 11 of the Internet which carries audio and video broadcasts. More 12 information about the MBONE is on the WWW at 13 <http://www-itg.lbl.gov/mbone/>. Information about the multicast 14 capabilities of the various network cards is contained in 15 <file:Documentation/networking/multicast.txt>. For most people, it's 16 safe to say N. 17 18config IP_ADVANCED_ROUTER 19 bool "IP: advanced router" 20 depends on INET 21 ---help--- 22 If you intend to run your Linux box mostly as a router, i.e. as a 23 computer that forwards and redistributes network packets, say Y; you 24 will then be presented with several options that allow more precise 25 control about the routing process. 26 27 The answer to this question won't directly affect the kernel: 28 answering N will just cause the configurator to skip all the 29 questions about advanced routing. 30 31 Note that your box can only act as a router if you enable IP 32 forwarding in your kernel; you can do that by saying Y to "/proc 33 file system support" and "Sysctl support" below and executing the 34 line 35 36 echo "1" > /proc/sys/net/ipv4/ip_forward 37 38 at boot time after the /proc file system has been mounted. 39 40 If you turn on IP forwarding, you will also get the rp_filter, which 41 automatically rejects incoming packets if the routing table entry 42 for their source address doesn't match the network interface they're 43 arriving on. This has security advantages because it prevents the 44 so-called IP spoofing, however it can pose problems if you use 45 asymmetric routing (packets from you to a host take a different path 46 than packets from that host to you) or if you operate a non-routing 47 host which has several IP addresses on different interfaces. To turn 48 rp_filter off use: 49 50 echo 0 > /proc/sys/net/ipv4/conf/<device>/rp_filter 51 or 52 echo 0 > /proc/sys/net/ipv4/conf/all/rp_filter 53 54 If unsure, say N here. 55 56choice 57 prompt "Choose IP: FIB lookup algorithm (choose FIB_HASH if unsure)" 58 depends on IP_ADVANCED_ROUTER 59 default IP_FIB_HASH 60 61config IP_FIB_HASH 62 bool "FIB_HASH" 63 ---help--- 64 Current FIB is very proven and good enough for most users. 65 66config IP_FIB_TRIE 67 bool "FIB_TRIE" 68 ---help--- 69 Use new experimental LC-trie as FIB lookup algoritm. 70 This improves lookup performance if you have a large 71 number of routes. 72 73 LC-trie is a longest matching prefix lookup algorithm which 74 performs better than FIB_HASH for large routing tables. 75 But, it consumes more memory and is more complex. 76 77 LC-trie is described in: 78 79 IP-address lookup using LC-tries. Stefan Nilsson and Gunnar Karlsson 80 IEEE Journal on Selected Areas in Communications, 17(6):1083-1092, June 1999 81 An experimental study of compression methods for dynamic tries 82 Stefan Nilsson and Matti Tikkanen. Algorithmica, 33(1):19-33, 2002. 83 http://www.nada.kth.se/~snilsson/public/papers/dyntrie2/ 84 85endchoice 86 87# If the user does not enable advanced routing, he gets the safe 88# default of the fib-hash algorithm. 89config IP_FIB_HASH 90 bool 91 depends on !IP_ADVANCED_ROUTER 92 default y 93 94config IP_MULTIPLE_TABLES 95 bool "IP: policy routing" 96 depends on IP_ADVANCED_ROUTER 97 ---help--- 98 Normally, a router decides what to do with a received packet based 99 solely on the packet's final destination address. If you say Y here, 100 the Linux router will also be able to take the packet's source 101 address into account. Furthermore, the TOS (Type-Of-Service) field 102 of the packet can be used for routing decisions as well. 103 104 If you are interested in this, please see the preliminary 105 documentation at <http://www.compendium.com.ar/policy-routing.txt> 106 and <ftp://post.tepkom.ru/pub/vol2/Linux/docs/advanced-routing.tex>. 107 You will need supporting software from 108 <ftp://ftp.tux.org/pub/net/ip-routing/>. 109 110 If unsure, say N. 111 112config IP_ROUTE_FWMARK 113 bool "IP: use netfilter MARK value as routing key" 114 depends on IP_MULTIPLE_TABLES && NETFILTER 115 help 116 If you say Y here, you will be able to specify different routes for 117 packets with different mark values (see iptables(8), MARK target). 118 119config IP_ROUTE_MULTIPATH 120 bool "IP: equal cost multipath" 121 depends on IP_ADVANCED_ROUTER 122 help 123 Normally, the routing tables specify a single action to be taken in 124 a deterministic manner for a given packet. If you say Y here 125 however, it becomes possible to attach several actions to a packet 126 pattern, in effect specifying several alternative paths to travel 127 for those packets. The router considers all these paths to be of 128 equal "cost" and chooses one of them in a non-deterministic fashion 129 if a matching packet arrives. 130 131config IP_ROUTE_MULTIPATH_CACHED 132 bool "IP: equal cost multipath with caching support (EXPERIMENTAL)" 133 depends on: IP_ROUTE_MULTIPATH 134 help 135 Normally, equal cost multipath routing is not supported by the 136 routing cache. If you say Y here, alternative routes are cached 137 and on cache lookup a route is chosen in a configurable fashion. 138 139 If unsure, say N. 140 141config IP_ROUTE_MULTIPATH_RR 142 tristate "MULTIPATH: round robin algorithm" 143 depends on IP_ROUTE_MULTIPATH_CACHED 144 help 145 Mulitpath routes are chosen according to Round Robin 146 147config IP_ROUTE_MULTIPATH_RANDOM 148 tristate "MULTIPATH: random algorithm" 149 depends on IP_ROUTE_MULTIPATH_CACHED 150 help 151 Multipath routes are chosen in a random fashion. Actually, 152 there is no weight for a route. The advantage of this policy 153 is that it is implemented stateless and therefore introduces only 154 a very small delay. 155 156config IP_ROUTE_MULTIPATH_WRANDOM 157 tristate "MULTIPATH: weighted random algorithm" 158 depends on IP_ROUTE_MULTIPATH_CACHED 159 help 160 Multipath routes are chosen in a weighted random fashion. 161 The per route weights are the weights visible via ip route 2. As the 162 corresponding state management introduces some overhead routing delay 163 is increased. 164 165config IP_ROUTE_MULTIPATH_DRR 166 tristate "MULTIPATH: interface round robin algorithm" 167 depends on IP_ROUTE_MULTIPATH_CACHED 168 help 169 Connections are distributed in a round robin fashion over the 170 available interfaces. This policy makes sense if the connections 171 should be primarily distributed on interfaces and not on routes. 172 173config IP_ROUTE_VERBOSE 174 bool "IP: verbose route monitoring" 175 depends on IP_ADVANCED_ROUTER 176 help 177 If you say Y here, which is recommended, then the kernel will print 178 verbose messages regarding the routing, for example warnings about 179 received packets which look strange and could be evidence of an 180 attack or a misconfigured system somewhere. The information is 181 handled by the klogd daemon which is responsible for kernel messages 182 ("man klogd"). 183 184config IP_PNP 185 bool "IP: kernel level autoconfiguration" 186 depends on INET 187 help 188 This enables automatic configuration of IP addresses of devices and 189 of the routing table during kernel boot, based on either information 190 supplied on the kernel command line or by BOOTP or RARP protocols. 191 You need to say Y only for diskless machines requiring network 192 access to boot (in which case you want to say Y to "Root file system 193 on NFS" as well), because all other machines configure the network 194 in their startup scripts. 195 196config IP_PNP_DHCP 197 bool "IP: DHCP support" 198 depends on IP_PNP 199 ---help--- 200 If you want your Linux box to mount its whole root file system (the 201 one containing the directory /) from some other computer over the 202 net via NFS and you want the IP address of your computer to be 203 discovered automatically at boot time using the DHCP protocol (a 204 special protocol designed for doing this job), say Y here. In case 205 the boot ROM of your network card was designed for booting Linux and 206 does DHCP itself, providing all necessary information on the kernel 207 command line, you can say N here. 208 209 If unsure, say Y. Note that if you want to use DHCP, a DHCP server 210 must be operating on your network. Read 211 <file:Documentation/nfsroot.txt> for details. 212 213config IP_PNP_BOOTP 214 bool "IP: BOOTP support" 215 depends on IP_PNP 216 ---help--- 217 If you want your Linux box to mount its whole root file system (the 218 one containing the directory /) from some other computer over the 219 net via NFS and you want the IP address of your computer to be 220 discovered automatically at boot time using the BOOTP protocol (a 221 special protocol designed for doing this job), say Y here. In case 222 the boot ROM of your network card was designed for booting Linux and 223 does BOOTP itself, providing all necessary information on the kernel 224 command line, you can say N here. If unsure, say Y. Note that if you 225 want to use BOOTP, a BOOTP server must be operating on your network. 226 Read <file:Documentation/nfsroot.txt> for details. 227 228config IP_PNP_RARP 229 bool "IP: RARP support" 230 depends on IP_PNP 231 help 232 If you want your Linux box to mount its whole root file system (the 233 one containing the directory /) from some other computer over the 234 net via NFS and you want the IP address of your computer to be 235 discovered automatically at boot time using the RARP protocol (an 236 older protocol which is being obsoleted by BOOTP and DHCP), say Y 237 here. Note that if you want to use RARP, a RARP server must be 238 operating on your network. Read <file:Documentation/nfsroot.txt> for 239 details. 240 241# not yet ready.. 242# bool ' IP: ARP support' CONFIG_IP_PNP_ARP 243config NET_IPIP 244 tristate "IP: tunneling" 245 depends on INET 246 select INET_TUNNEL 247 ---help--- 248 Tunneling means encapsulating data of one protocol type within 249 another protocol and sending it over a channel that understands the 250 encapsulating protocol. This particular tunneling driver implements 251 encapsulation of IP within IP, which sounds kind of pointless, but 252 can be useful if you want to make your (or some other) machine 253 appear on a different network than it physically is, or to use 254 mobile-IP facilities (allowing laptops to seamlessly move between 255 networks without changing their IP addresses). 256 257 Saying Y to this option will produce two modules ( = code which can 258 be inserted in and removed from the running kernel whenever you 259 want). Most people won't need this and can say N. 260 261config NET_IPGRE 262 tristate "IP: GRE tunnels over IP" 263 depends on INET 264 select XFRM 265 help 266 Tunneling means encapsulating data of one protocol type within 267 another protocol and sending it over a channel that understands the 268 encapsulating protocol. This particular tunneling driver implements 269 GRE (Generic Routing Encapsulation) and at this time allows 270 encapsulating of IPv4 or IPv6 over existing IPv4 infrastructure. 271 This driver is useful if the other endpoint is a Cisco router: Cisco 272 likes GRE much better than the other Linux tunneling driver ("IP 273 tunneling" above). In addition, GRE allows multicast redistribution 274 through the tunnel. 275 276config NET_IPGRE_BROADCAST 277 bool "IP: broadcast GRE over IP" 278 depends on IP_MULTICAST && NET_IPGRE 279 help 280 One application of GRE/IP is to construct a broadcast WAN (Wide Area 281 Network), which looks like a normal Ethernet LAN (Local Area 282 Network), but can be distributed all over the Internet. If you want 283 to do that, say Y here and to "IP multicast routing" below. 284 285config IP_MROUTE 286 bool "IP: multicast routing" 287 depends on IP_MULTICAST 288 help 289 This is used if you want your machine to act as a router for IP 290 packets that have several destination addresses. It is needed on the 291 MBONE, a high bandwidth network on top of the Internet which carries 292 audio and video broadcasts. In order to do that, you would most 293 likely run the program mrouted. Information about the multicast 294 capabilities of the various network cards is contained in 295 <file:Documentation/networking/multicast.txt>. If you haven't heard 296 about it, you don't need it. 297 298config IP_PIMSM_V1 299 bool "IP: PIM-SM version 1 support" 300 depends on IP_MROUTE 301 help 302 Kernel side support for Sparse Mode PIM (Protocol Independent 303 Multicast) version 1. This multicast routing protocol is used widely 304 because Cisco supports it. You need special software to use it 305 (pimd-v1). Please see <http://netweb.usc.edu/pim/> for more 306 information about PIM. 307 308 Say Y if you want to use PIM-SM v1. Note that you can say N here if 309 you just want to use Dense Mode PIM. 310 311config IP_PIMSM_V2 312 bool "IP: PIM-SM version 2 support" 313 depends on IP_MROUTE 314 help 315 Kernel side support for Sparse Mode PIM version 2. In order to use 316 this, you need an experimental routing daemon supporting it (pimd or 317 gated-5). This routing protocol is not used widely, so say N unless 318 you want to play with it. 319 320config ARPD 321 bool "IP: ARP daemon support (EXPERIMENTAL)" 322 depends on INET && EXPERIMENTAL 323 ---help--- 324 Normally, the kernel maintains an internal cache which maps IP 325 addresses to hardware addresses on the local network, so that 326 Ethernet/Token Ring/ etc. frames are sent to the proper address on 327 the physical networking layer. For small networks having a few 328 hundred directly connected hosts or less, keeping this address 329 resolution (ARP) cache inside the kernel works well. However, 330 maintaining an internal ARP cache does not work well for very large 331 switched networks, and will use a lot of kernel memory if TCP/IP 332 connections are made to many machines on the network. 333 334 If you say Y here, the kernel's internal ARP cache will never grow 335 to more than 256 entries (the oldest entries are expired in a LIFO 336 manner) and communication will be attempted with the user space ARP 337 daemon arpd. Arpd then answers the address resolution request either 338 from its own cache or by asking the net. 339 340 This code is experimental and also obsolete. If you want to use it, 341 you need to find a version of the daemon arpd on the net somewhere, 342 and you should also say Y to "Kernel/User network link driver", 343 below. If unsure, say N. 344 345config SYN_COOKIES 346 bool "IP: TCP syncookie support (disabled per default)" 347 depends on INET 348 ---help--- 349 Normal TCP/IP networking is open to an attack known as "SYN 350 flooding". This denial-of-service attack prevents legitimate remote 351 users from being able to connect to your computer during an ongoing 352 attack and requires very little work from the attacker, who can 353 operate from anywhere on the Internet. 354 355 SYN cookies provide protection against this type of attack. If you 356 say Y here, the TCP/IP stack will use a cryptographic challenge 357 protocol known as "SYN cookies" to enable legitimate users to 358 continue to connect, even when your machine is under attack. There 359 is no need for the legitimate users to change their TCP/IP software; 360 SYN cookies work transparently to them. For technical information 361 about SYN cookies, check out <http://cr.yp.to/syncookies.html>. 362 363 If you are SYN flooded, the source address reported by the kernel is 364 likely to have been forged by the attacker; it is only reported as 365 an aid in tracing the packets to their actual source and should not 366 be taken as absolute truth. 367 368 SYN cookies may prevent correct error reporting on clients when the 369 server is really overloaded. If this happens frequently better turn 370 them off. 371 372 If you say Y here, note that SYN cookies aren't enabled by default; 373 you can enable them by saying Y to "/proc file system support" and 374 "Sysctl support" below and executing the command 375 376 echo 1 >/proc/sys/net/ipv4/tcp_syncookies 377 378 at boot time after the /proc file system has been mounted. 379 380 If unsure, say N. 381 382config INET_AH 383 tristate "IP: AH transformation" 384 depends on INET 385 select XFRM 386 select CRYPTO 387 select CRYPTO_HMAC 388 select CRYPTO_MD5 389 select CRYPTO_SHA1 390 ---help--- 391 Support for IPsec AH. 392 393 If unsure, say Y. 394 395config INET_ESP 396 tristate "IP: ESP transformation" 397 depends on INET 398 select XFRM 399 select CRYPTO 400 select CRYPTO_HMAC 401 select CRYPTO_MD5 402 select CRYPTO_SHA1 403 select CRYPTO_DES 404 ---help--- 405 Support for IPsec ESP. 406 407 If unsure, say Y. 408 409config INET_IPCOMP 410 tristate "IP: IPComp transformation" 411 depends on INET 412 select XFRM 413 select INET_TUNNEL 414 select CRYPTO 415 select CRYPTO_DEFLATE 416 ---help--- 417 Support for IP Payload Compression Protocol (IPComp) (RFC3173), 418 typically needed for IPsec. 419 420 If unsure, say Y. 421 422config INET_TUNNEL 423 tristate "IP: tunnel transformation" 424 depends on INET 425 select XFRM 426 ---help--- 427 Support for generic IP tunnel transformation, which is required by 428 the IP tunneling module as well as tunnel mode IPComp. 429 430 If unsure, say Y. 431 432config IP_TCPDIAG 433 tristate "IP: TCP socket monitoring interface" 434 depends on INET 435 default y 436 ---help--- 437 Support for TCP socket monitoring interface used by native Linux 438 tools such as ss. ss is included in iproute2, currently downloadable 439 at <http://developer.osdl.org/dev/iproute2>. If you want IPv6 support 440 and have selected IPv6 as a module, you need to build this as a 441 module too. 442 443 If unsure, say Y. 444 445config IP_TCPDIAG_IPV6 446 def_bool (IP_TCPDIAG=y && IPV6=y) || (IP_TCPDIAG=m && IPV6) 447 448config TCP_CONG_ADVANCED 449 bool "TCP: advanced congestion control" 450 depends on INET 451 ---help--- 452 Support for selection of various TCP congestion control 453 modules. 454 455 Nearly all users can safely say no here, and a safe default 456 selection will be made (BIC-TCP with new Reno as a fallback). 457 458 If unsure, say N. 459 460# TCP Reno is builtin (required as fallback) 461menu "TCP congestion control" 462 depends on TCP_CONG_ADVANCED 463 464config TCP_CONG_BIC 465 tristate "Binary Increase Congestion (BIC) control" 466 depends on INET 467 default y 468 ---help--- 469 BIC-TCP is a sender-side only change that ensures a linear RTT 470 fairness under large windows while offering both scalability and 471 bounded TCP-friendliness. The protocol combines two schemes 472 called additive increase and binary search increase. When the 473 congestion window is large, additive increase with a large 474 increment ensures linear RTT fairness as well as good 475 scalability. Under small congestion windows, binary search 476 increase provides TCP friendliness. 477 See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/ 478 479config TCP_CONG_WESTWOOD 480 tristate "TCP Westwood+" 481 depends on INET 482 default m 483 ---help--- 484 TCP Westwood+ is a sender-side only modification of the TCP Reno 485 protocol stack that optimizes the performance of TCP congestion 486 control. It is based on end-to-end bandwidth estimation to set 487 congestion window and slow start threshold after a congestion 488 episode. Using this estimation, TCP Westwood+ adaptively sets a 489 slow start threshold and a congestion window which takes into 490 account the bandwidth used at the time congestion is experienced. 491 TCP Westwood+ significantly increases fairness wrt TCP Reno in 492 wired networks and throughput over wireless links. 493 494config TCP_CONG_HTCP 495 tristate "H-TCP" 496 depends on INET 497 default m 498 ---help--- 499 H-TCP is a send-side only modifications of the TCP Reno 500 protocol stack that optimizes the performance of TCP 501 congestion control for high speed network links. It uses a 502 modeswitch to change the alpha and beta parameters of TCP Reno 503 based on network conditions and in a way so as to be fair with 504 other Reno and H-TCP flows. 505 506config TCP_CONG_HSTCP 507 tristate "High Speed TCP" 508 depends on INET && EXPERIMENTAL 509 default n 510 ---help--- 511 Sally Floyd's High Speed TCP (RFC 3649) congestion control. 512 A modification to TCP's congestion control mechanism for use 513 with large congestion windows. A table indicates how much to 514 increase the congestion window by when an ACK is received. 515 For more detail see http://www.icir.org/floyd/hstcp.html 516 517config TCP_CONG_HYBLA 518 tristate "TCP-Hybla congestion control algorithm" 519 depends on INET && EXPERIMENTAL 520 default n 521 ---help--- 522 TCP-Hybla is a sender-side only change that eliminates penalization of 523 long-RTT, large-bandwidth connections, like when satellite legs are 524 involved, expecially when sharing a common bottleneck with normal 525 terrestrial connections. 526 527config TCP_CONG_VEGAS 528 tristate "TCP Vegas" 529 depends on INET && EXPERIMENTAL 530 default n 531 ---help--- 532 TCP Vegas is a sender-side only change to TCP that anticipates 533 the onset of congestion by estimating the bandwidth. TCP Vegas 534 adjusts the sending rate by modifying the congestion 535 window. TCP Vegas should provide less packet loss, but it is 536 not as aggressive as TCP Reno. 537 538config TCP_CONG_SCALABLE 539 tristate "Scalable TCP" 540 depends on INET && EXPERIMENTAL 541 default n 542 ---help--- 543 Scalable TCP is a sender-side only change to TCP which uses a 544 MIMD congestion control algorithm which has some nice scaling 545 properties, though is known to have fairness issues. 546 See http://www-lce.eng.cam.ac.uk/~ctk21/scalable/ 547 548endmenu 549 550config TCP_CONG_BIC 551 tristate 552 depends on !TCP_CONG_ADVANCED 553 default y 554 555source "net/ipv4/ipvs/Kconfig" 556 557