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 NET_UDP_TUNNEL 311 tristate 312 default n 313 314config INET_AH 315 tristate "IP: AH transformation" 316 select XFRM_ALGO 317 select CRYPTO 318 select CRYPTO_HMAC 319 select CRYPTO_MD5 320 select CRYPTO_SHA1 321 ---help--- 322 Support for IPsec AH. 323 324 If unsure, say Y. 325 326config INET_ESP 327 tristate "IP: ESP transformation" 328 select XFRM_ALGO 329 select CRYPTO 330 select CRYPTO_AUTHENC 331 select CRYPTO_HMAC 332 select CRYPTO_MD5 333 select CRYPTO_CBC 334 select CRYPTO_SHA1 335 select CRYPTO_DES 336 ---help--- 337 Support for IPsec ESP. 338 339 If unsure, say Y. 340 341config INET_IPCOMP 342 tristate "IP: IPComp transformation" 343 select INET_XFRM_TUNNEL 344 select XFRM_IPCOMP 345 ---help--- 346 Support for IP Payload Compression Protocol (IPComp) (RFC3173), 347 typically needed for IPsec. 348 349 If unsure, say Y. 350 351config INET_XFRM_TUNNEL 352 tristate 353 select INET_TUNNEL 354 default n 355 356config INET_TUNNEL 357 tristate 358 default n 359 360config INET_XFRM_MODE_TRANSPORT 361 tristate "IP: IPsec transport mode" 362 default y 363 select XFRM 364 ---help--- 365 Support for IPsec transport mode. 366 367 If unsure, say Y. 368 369config INET_XFRM_MODE_TUNNEL 370 tristate "IP: IPsec tunnel mode" 371 default y 372 select XFRM 373 ---help--- 374 Support for IPsec tunnel mode. 375 376 If unsure, say Y. 377 378config INET_XFRM_MODE_BEET 379 tristate "IP: IPsec BEET mode" 380 default y 381 select XFRM 382 ---help--- 383 Support for IPsec BEET mode. 384 385 If unsure, say Y. 386 387config INET_LRO 388 tristate "Large Receive Offload (ipv4/tcp)" 389 default y 390 ---help--- 391 Support for Large Receive Offload (ipv4/tcp). 392 393 If unsure, say Y. 394 395config INET_DIAG 396 tristate "INET: socket monitoring interface" 397 default y 398 ---help--- 399 Support for INET (TCP, DCCP, etc) socket monitoring interface used by 400 native Linux tools such as ss. ss is included in iproute2, currently 401 downloadable at: 402 403 http://www.linuxfoundation.org/collaborate/workgroups/networking/iproute2 404 405 If unsure, say Y. 406 407config INET_TCP_DIAG 408 depends on INET_DIAG 409 def_tristate INET_DIAG 410 411config INET_UDP_DIAG 412 tristate "UDP: socket monitoring interface" 413 depends on INET_DIAG && (IPV6 || IPV6=n) 414 default n 415 ---help--- 416 Support for UDP socket monitoring interface used by the ss tool. 417 If unsure, say Y. 418 419menuconfig TCP_CONG_ADVANCED 420 bool "TCP: advanced congestion control" 421 ---help--- 422 Support for selection of various TCP congestion control 423 modules. 424 425 Nearly all users can safely say no here, and a safe default 426 selection will be made (CUBIC with new Reno as a fallback). 427 428 If unsure, say N. 429 430if TCP_CONG_ADVANCED 431 432config TCP_CONG_BIC 433 tristate "Binary Increase Congestion (BIC) control" 434 default m 435 ---help--- 436 BIC-TCP is a sender-side only change that ensures a linear RTT 437 fairness under large windows while offering both scalability and 438 bounded TCP-friendliness. The protocol combines two schemes 439 called additive increase and binary search increase. When the 440 congestion window is large, additive increase with a large 441 increment ensures linear RTT fairness as well as good 442 scalability. Under small congestion windows, binary search 443 increase provides TCP friendliness. 444 See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/ 445 446config TCP_CONG_CUBIC 447 tristate "CUBIC TCP" 448 default y 449 ---help--- 450 This is version 2.0 of BIC-TCP which uses a cubic growth function 451 among other techniques. 452 See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/cubic-paper.pdf 453 454config TCP_CONG_WESTWOOD 455 tristate "TCP Westwood+" 456 default m 457 ---help--- 458 TCP Westwood+ is a sender-side only modification of the TCP Reno 459 protocol stack that optimizes the performance of TCP congestion 460 control. It is based on end-to-end bandwidth estimation to set 461 congestion window and slow start threshold after a congestion 462 episode. Using this estimation, TCP Westwood+ adaptively sets a 463 slow start threshold and a congestion window which takes into 464 account the bandwidth used at the time congestion is experienced. 465 TCP Westwood+ significantly increases fairness wrt TCP Reno in 466 wired networks and throughput over wireless links. 467 468config TCP_CONG_HTCP 469 tristate "H-TCP" 470 default m 471 ---help--- 472 H-TCP is a send-side only modifications of the TCP Reno 473 protocol stack that optimizes the performance of TCP 474 congestion control for high speed network links. It uses a 475 modeswitch to change the alpha and beta parameters of TCP Reno 476 based on network conditions and in a way so as to be fair with 477 other Reno and H-TCP flows. 478 479config TCP_CONG_HSTCP 480 tristate "High Speed TCP" 481 default n 482 ---help--- 483 Sally Floyd's High Speed TCP (RFC 3649) congestion control. 484 A modification to TCP's congestion control mechanism for use 485 with large congestion windows. A table indicates how much to 486 increase the congestion window by when an ACK is received. 487 For more detail see http://www.icir.org/floyd/hstcp.html 488 489config TCP_CONG_HYBLA 490 tristate "TCP-Hybla congestion control algorithm" 491 default n 492 ---help--- 493 TCP-Hybla is a sender-side only change that eliminates penalization of 494 long-RTT, large-bandwidth connections, like when satellite legs are 495 involved, especially when sharing a common bottleneck with normal 496 terrestrial connections. 497 498config TCP_CONG_VEGAS 499 tristate "TCP Vegas" 500 default n 501 ---help--- 502 TCP Vegas is a sender-side only change to TCP that anticipates 503 the onset of congestion by estimating the bandwidth. TCP Vegas 504 adjusts the sending rate by modifying the congestion 505 window. TCP Vegas should provide less packet loss, but it is 506 not as aggressive as TCP Reno. 507 508config TCP_CONG_SCALABLE 509 tristate "Scalable TCP" 510 default n 511 ---help--- 512 Scalable TCP is a sender-side only change to TCP which uses a 513 MIMD congestion control algorithm which has some nice scaling 514 properties, though is known to have fairness issues. 515 See http://www.deneholme.net/tom/scalable/ 516 517config TCP_CONG_LP 518 tristate "TCP Low Priority" 519 default n 520 ---help--- 521 TCP Low Priority (TCP-LP), a distributed algorithm whose goal is 522 to utilize only the excess network bandwidth as compared to the 523 ``fair share`` of bandwidth as targeted by TCP. 524 See http://www-ece.rice.edu/networks/TCP-LP/ 525 526config TCP_CONG_VENO 527 tristate "TCP Veno" 528 default n 529 ---help--- 530 TCP Veno is a sender-side only enhancement of TCP to obtain better 531 throughput over wireless networks. TCP Veno makes use of state 532 distinguishing to circumvent the difficult judgment of the packet loss 533 type. TCP Veno cuts down less congestion window in response to random 534 loss packets. 535 See <http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1177186> 536 537config TCP_CONG_YEAH 538 tristate "YeAH TCP" 539 select TCP_CONG_VEGAS 540 default n 541 ---help--- 542 YeAH-TCP is a sender-side high-speed enabled TCP congestion control 543 algorithm, which uses a mixed loss/delay approach to compute the 544 congestion window. It's design goals target high efficiency, 545 internal, RTT and Reno fairness, resilience to link loss while 546 keeping network elements load as low as possible. 547 548 For further details look here: 549 http://wil.cs.caltech.edu/pfldnet2007/paper/YeAH_TCP.pdf 550 551config TCP_CONG_ILLINOIS 552 tristate "TCP Illinois" 553 default n 554 ---help--- 555 TCP-Illinois is a sender-side modification of TCP Reno for 556 high speed long delay links. It uses round-trip-time to 557 adjust the alpha and beta parameters to achieve a higher average 558 throughput and maintain fairness. 559 560 For further details see: 561 http://www.ews.uiuc.edu/~shaoliu/tcpillinois/index.html 562 563choice 564 prompt "Default TCP congestion control" 565 default DEFAULT_CUBIC 566 help 567 Select the TCP congestion control that will be used by default 568 for all connections. 569 570 config DEFAULT_BIC 571 bool "Bic" if TCP_CONG_BIC=y 572 573 config DEFAULT_CUBIC 574 bool "Cubic" if TCP_CONG_CUBIC=y 575 576 config DEFAULT_HTCP 577 bool "Htcp" if TCP_CONG_HTCP=y 578 579 config DEFAULT_HYBLA 580 bool "Hybla" if TCP_CONG_HYBLA=y 581 582 config DEFAULT_VEGAS 583 bool "Vegas" if TCP_CONG_VEGAS=y 584 585 config DEFAULT_VENO 586 bool "Veno" if TCP_CONG_VENO=y 587 588 config DEFAULT_WESTWOOD 589 bool "Westwood" if TCP_CONG_WESTWOOD=y 590 591 config DEFAULT_RENO 592 bool "Reno" 593 594endchoice 595 596endif 597 598config TCP_CONG_CUBIC 599 tristate 600 depends on !TCP_CONG_ADVANCED 601 default y 602 603config DEFAULT_TCP_CONG 604 string 605 default "bic" if DEFAULT_BIC 606 default "cubic" if DEFAULT_CUBIC 607 default "htcp" if DEFAULT_HTCP 608 default "hybla" if DEFAULT_HYBLA 609 default "vegas" if DEFAULT_VEGAS 610 default "westwood" if DEFAULT_WESTWOOD 611 default "veno" if DEFAULT_VENO 612 default "reno" if DEFAULT_RENO 613 default "cubic" 614 615config TCP_MD5SIG 616 bool "TCP: MD5 Signature Option support (RFC2385)" 617 select CRYPTO 618 select CRYPTO_MD5 619 ---help--- 620 RFC2385 specifies a method of giving MD5 protection to TCP sessions. 621 Its main (only?) use is to protect BGP sessions between core routers 622 on the Internet. 623 624 If unsure, say N. 625