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