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.savetz.com/mbone/>. For most people, it's safe to say N. 13 14config IP_ADVANCED_ROUTER 15 bool "IP: advanced router" 16 ---help--- 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. 21 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. 25 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 29 line 30 31 echo "1" > /proc/sys/net/ipv4/ip_forward 32 33 at boot time after the /proc file system has been mounted. 34 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 43 rp_filter on use: 44 45 echo 1 > /proc/sys/net/ipv4/conf/<device>/rp_filter 46 or 47 echo 1 > /proc/sys/net/ipv4/conf/all/rp_filter 48 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>. 52 53 If unsure, say N here. 54 55config IP_FIB_TRIE_STATS 56 bool "FIB TRIE statistics" 57 depends on IP_ADVANCED_ROUTER 58 ---help--- 59 Keep track of statistics on structure of FIB TRIE table. 60 Useful for testing and measuring TRIE performance. 61 62config IP_MULTIPLE_TABLES 63 bool "IP: policy routing" 64 depends on IP_ADVANCED_ROUTER 65 select FIB_RULES 66 ---help--- 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. 72 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/>. 78 79 If unsure, say N. 80 81config IP_ROUTE_MULTIPATH 82 bool "IP: equal cost multipath" 83 depends on IP_ADVANCED_ROUTER 84 help 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. 92 93config IP_ROUTE_VERBOSE 94 bool "IP: verbose route monitoring" 95 depends on IP_ADVANCED_ROUTER 96 help 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 102 ("man klogd"). 103 104config IP_ROUTE_CLASSID 105 bool 106 107config IP_PNP 108 bool "IP: kernel level autoconfiguration" 109 help 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. 117 118config IP_PNP_DHCP 119 bool "IP: DHCP support" 120 depends on IP_PNP 121 ---help--- 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. 130 131 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. 134 135config IP_PNP_BOOTP 136 bool "IP: BOOTP support" 137 depends on IP_PNP 138 ---help--- 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. 149 150config IP_PNP_RARP 151 bool "IP: RARP support" 152 depends on IP_PNP 153 help 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. 162 163config NET_IPIP 164 tristate "IP: tunneling" 165 select INET_TUNNEL 166 select NET_IP_TUNNEL 167 ---help--- 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). 176 177 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. 180 181config NET_IPGRE_DEMUX 182 tristate "IP: GRE demultiplexer" 183 help 184 This is helper module to demultiplex GRE packets on GRE version field criteria. 185 Required by ip_gre and pptp modules. 186 187config NET_IP_TUNNEL 188 tristate 189 default n 190 191config NET_IPGRE 192 tristate "IP: GRE tunnels over IP" 193 depends on (IPV6 || IPV6=n) && NET_IPGRE_DEMUX 194 select NET_IP_TUNNEL 195 help 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 204 through the tunnel. 205 206config NET_IPGRE_BROADCAST 207 bool "IP: broadcast GRE over IP" 208 depends on IP_MULTICAST && NET_IPGRE 209 help 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. 214 215config IP_MROUTE 216 bool "IP: multicast routing" 217 depends on IP_MULTICAST 218 help 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 224 don't need it. 225 226config IP_MROUTE_MULTIPLE_TABLES 227 bool "IP: multicast policy routing" 228 depends on IP_MROUTE && IP_ADVANCED_ROUTER 229 select FIB_RULES 230 help 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. 237 238 If unsure, say N. 239 240config IP_PIMSM_V1 241 bool "IP: PIM-SM version 1 support" 242 depends on IP_MROUTE 243 help 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. 249 250 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. 252 253config IP_PIMSM_V2 254 bool "IP: PIM-SM version 2 support" 255 depends on IP_MROUTE 256 help 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. 261 262config SYN_COOKIES 263 bool "IP: TCP syncookie support" 264 ---help--- 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. 270 271 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>. 278 279 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. 283 284 SYN cookies may prevent correct error reporting on clients when the 285 server is really overloaded. If this happens frequently better turn 286 them off. 287 288 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 291 292 echo 0 > /proc/sys/net/ipv4/tcp_syncookies 293 294 after the /proc file system has been mounted. 295 296 If unsure, say N. 297 298config NET_IPVTI 299 tristate "Virtual (secure) IP: tunneling" 300 select INET_TUNNEL 301 select NET_IP_TUNNEL 302 depends on INET_XFRM_MODE_TUNNEL 303 ---help--- 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 308 on top. 309 310config INET_AH 311 tristate "IP: AH transformation" 312 select XFRM_ALGO 313 select CRYPTO 314 select CRYPTO_HMAC 315 select CRYPTO_MD5 316 select CRYPTO_SHA1 317 ---help--- 318 Support for IPsec AH. 319 320 If unsure, say Y. 321 322config INET_ESP 323 tristate "IP: ESP transformation" 324 select XFRM_ALGO 325 select CRYPTO 326 select CRYPTO_AUTHENC 327 select CRYPTO_HMAC 328 select CRYPTO_MD5 329 select CRYPTO_CBC 330 select CRYPTO_SHA1 331 select CRYPTO_DES 332 ---help--- 333 Support for IPsec ESP. 334 335 If unsure, say Y. 336 337config INET_IPCOMP 338 tristate "IP: IPComp transformation" 339 select INET_XFRM_TUNNEL 340 select XFRM_IPCOMP 341 ---help--- 342 Support for IP Payload Compression Protocol (IPComp) (RFC3173), 343 typically needed for IPsec. 344 345 If unsure, say Y. 346 347config INET_XFRM_TUNNEL 348 tristate 349 select INET_TUNNEL 350 default n 351 352config INET_TUNNEL 353 tristate 354 default n 355 356config INET_XFRM_MODE_TRANSPORT 357 tristate "IP: IPsec transport mode" 358 default y 359 select XFRM 360 ---help--- 361 Support for IPsec transport mode. 362 363 If unsure, say Y. 364 365config INET_XFRM_MODE_TUNNEL 366 tristate "IP: IPsec tunnel mode" 367 default y 368 select XFRM 369 ---help--- 370 Support for IPsec tunnel mode. 371 372 If unsure, say Y. 373 374config INET_XFRM_MODE_BEET 375 tristate "IP: IPsec BEET mode" 376 default y 377 select XFRM 378 ---help--- 379 Support for IPsec BEET mode. 380 381 If unsure, say Y. 382 383config INET_LRO 384 tristate "Large Receive Offload (ipv4/tcp)" 385 default y 386 ---help--- 387 Support for Large Receive Offload (ipv4/tcp). 388 389 If unsure, say Y. 390 391config INET_DIAG 392 tristate "INET: socket monitoring interface" 393 default y 394 ---help--- 395 Support for INET (TCP, DCCP, etc) socket monitoring interface used by 396 native Linux tools such as ss. ss is included in iproute2, currently 397 downloadable at: 398 399 http://www.linuxfoundation.org/collaborate/workgroups/networking/iproute2 400 401 If unsure, say Y. 402 403config INET_TCP_DIAG 404 depends on INET_DIAG 405 def_tristate INET_DIAG 406 407config INET_UDP_DIAG 408 tristate "UDP: socket monitoring interface" 409 depends on INET_DIAG && (IPV6 || IPV6=n) 410 default n 411 ---help--- 412 Support for UDP socket monitoring interface used by the ss tool. 413 If unsure, say Y. 414 415menuconfig TCP_CONG_ADVANCED 416 bool "TCP: advanced congestion control" 417 ---help--- 418 Support for selection of various TCP congestion control 419 modules. 420 421 Nearly all users can safely say no here, and a safe default 422 selection will be made (CUBIC with new Reno as a fallback). 423 424 If unsure, say N. 425 426if TCP_CONG_ADVANCED 427 428config TCP_CONG_BIC 429 tristate "Binary Increase Congestion (BIC) control" 430 default m 431 ---help--- 432 BIC-TCP is a sender-side only change that ensures a linear RTT 433 fairness under large windows while offering both scalability and 434 bounded TCP-friendliness. The protocol combines two schemes 435 called additive increase and binary search increase. When the 436 congestion window is large, additive increase with a large 437 increment ensures linear RTT fairness as well as good 438 scalability. Under small congestion windows, binary search 439 increase provides TCP friendliness. 440 See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/ 441 442config TCP_CONG_CUBIC 443 tristate "CUBIC TCP" 444 default y 445 ---help--- 446 This is version 2.0 of BIC-TCP which uses a cubic growth function 447 among other techniques. 448 See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/cubic-paper.pdf 449 450config TCP_CONG_WESTWOOD 451 tristate "TCP Westwood+" 452 default m 453 ---help--- 454 TCP Westwood+ is a sender-side only modification of the TCP Reno 455 protocol stack that optimizes the performance of TCP congestion 456 control. It is based on end-to-end bandwidth estimation to set 457 congestion window and slow start threshold after a congestion 458 episode. Using this estimation, TCP Westwood+ adaptively sets a 459 slow start threshold and a congestion window which takes into 460 account the bandwidth used at the time congestion is experienced. 461 TCP Westwood+ significantly increases fairness wrt TCP Reno in 462 wired networks and throughput over wireless links. 463 464config TCP_CONG_HTCP 465 tristate "H-TCP" 466 default m 467 ---help--- 468 H-TCP is a send-side only modifications of the TCP Reno 469 protocol stack that optimizes the performance of TCP 470 congestion control for high speed network links. It uses a 471 modeswitch to change the alpha and beta parameters of TCP Reno 472 based on network conditions and in a way so as to be fair with 473 other Reno and H-TCP flows. 474 475config TCP_CONG_HSTCP 476 tristate "High Speed TCP" 477 default n 478 ---help--- 479 Sally Floyd's High Speed TCP (RFC 3649) congestion control. 480 A modification to TCP's congestion control mechanism for use 481 with large congestion windows. A table indicates how much to 482 increase the congestion window by when an ACK is received. 483 For more detail see http://www.icir.org/floyd/hstcp.html 484 485config TCP_CONG_HYBLA 486 tristate "TCP-Hybla congestion control algorithm" 487 default n 488 ---help--- 489 TCP-Hybla is a sender-side only change that eliminates penalization of 490 long-RTT, large-bandwidth connections, like when satellite legs are 491 involved, especially when sharing a common bottleneck with normal 492 terrestrial connections. 493 494config TCP_CONG_VEGAS 495 tristate "TCP Vegas" 496 default n 497 ---help--- 498 TCP Vegas is a sender-side only change to TCP that anticipates 499 the onset of congestion by estimating the bandwidth. TCP Vegas 500 adjusts the sending rate by modifying the congestion 501 window. TCP Vegas should provide less packet loss, but it is 502 not as aggressive as TCP Reno. 503 504config TCP_CONG_SCALABLE 505 tristate "Scalable TCP" 506 default n 507 ---help--- 508 Scalable TCP is a sender-side only change to TCP which uses a 509 MIMD congestion control algorithm which has some nice scaling 510 properties, though is known to have fairness issues. 511 See http://www.deneholme.net/tom/scalable/ 512 513config TCP_CONG_LP 514 tristate "TCP Low Priority" 515 default n 516 ---help--- 517 TCP Low Priority (TCP-LP), a distributed algorithm whose goal is 518 to utilize only the excess network bandwidth as compared to the 519 ``fair share`` of bandwidth as targeted by TCP. 520 See http://www-ece.rice.edu/networks/TCP-LP/ 521 522config TCP_CONG_VENO 523 tristate "TCP Veno" 524 default n 525 ---help--- 526 TCP Veno is a sender-side only enhancement of TCP to obtain better 527 throughput over wireless networks. TCP Veno makes use of state 528 distinguishing to circumvent the difficult judgment of the packet loss 529 type. TCP Veno cuts down less congestion window in response to random 530 loss packets. 531 See <http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1177186> 532 533config TCP_CONG_YEAH 534 tristate "YeAH TCP" 535 select TCP_CONG_VEGAS 536 default n 537 ---help--- 538 YeAH-TCP is a sender-side high-speed enabled TCP congestion control 539 algorithm, which uses a mixed loss/delay approach to compute the 540 congestion window. It's design goals target high efficiency, 541 internal, RTT and Reno fairness, resilience to link loss while 542 keeping network elements load as low as possible. 543 544 For further details look here: 545 http://wil.cs.caltech.edu/pfldnet2007/paper/YeAH_TCP.pdf 546 547config TCP_CONG_ILLINOIS 548 tristate "TCP Illinois" 549 default n 550 ---help--- 551 TCP-Illinois is a sender-side modification of TCP Reno for 552 high speed long delay links. It uses round-trip-time to 553 adjust the alpha and beta parameters to achieve a higher average 554 throughput and maintain fairness. 555 556 For further details see: 557 http://www.ews.uiuc.edu/~shaoliu/tcpillinois/index.html 558 559choice 560 prompt "Default TCP congestion control" 561 default DEFAULT_CUBIC 562 help 563 Select the TCP congestion control that will be used by default 564 for all connections. 565 566 config DEFAULT_BIC 567 bool "Bic" if TCP_CONG_BIC=y 568 569 config DEFAULT_CUBIC 570 bool "Cubic" if TCP_CONG_CUBIC=y 571 572 config DEFAULT_HTCP 573 bool "Htcp" if TCP_CONG_HTCP=y 574 575 config DEFAULT_HYBLA 576 bool "Hybla" if TCP_CONG_HYBLA=y 577 578 config DEFAULT_VEGAS 579 bool "Vegas" if TCP_CONG_VEGAS=y 580 581 config DEFAULT_VENO 582 bool "Veno" if TCP_CONG_VENO=y 583 584 config DEFAULT_WESTWOOD 585 bool "Westwood" if TCP_CONG_WESTWOOD=y 586 587 config DEFAULT_RENO 588 bool "Reno" 589 590endchoice 591 592endif 593 594config TCP_CONG_CUBIC 595 tristate 596 depends on !TCP_CONG_ADVANCED 597 default y 598 599config DEFAULT_TCP_CONG 600 string 601 default "bic" if DEFAULT_BIC 602 default "cubic" if DEFAULT_CUBIC 603 default "htcp" if DEFAULT_HTCP 604 default "hybla" if DEFAULT_HYBLA 605 default "vegas" if DEFAULT_VEGAS 606 default "westwood" if DEFAULT_WESTWOOD 607 default "veno" if DEFAULT_VENO 608 default "reno" if DEFAULT_RENO 609 default "cubic" 610 611config TCP_MD5SIG 612 bool "TCP: MD5 Signature Option support (RFC2385)" 613 select CRYPTO 614 select CRYPTO_MD5 615 ---help--- 616 RFC2385 specifies a method of giving MD5 protection to TCP sessions. 617 Its main (only?) use is to protect BGP sessions between core routers 618 on the Internet. 619 620 If unsure, say N. 621