net/netfilter/Kconfig

   1 menu "Core Netfilter Configuration"
   2         depends on NET && INET && NETFILTER
   3
   4 config NETFILTER_NETLINK
   5         tristate
   6
   7 config NETFILTER_NETLINK_ACCT
   8 tristate "Netfilter NFACCT over NFNETLINK interface"
   9         depends on NETFILTER_ADVANCED
  10         select NETFILTER_NETLINK
  11         help
  12           If this option is enabled, the kernel will include support
  13           for extended accounting via NFNETLINK.
  14
  15 config NETFILTER_NETLINK_QUEUE
  16         tristate "Netfilter NFQUEUE over NFNETLINK interface"
  17         depends on NETFILTER_ADVANCED
  18         select NETFILTER_NETLINK
  19         help
  20           If this option is enabled, the kernel will include support
  21           for queueing packets via NFNETLINK.
  22
  23 config NETFILTER_NETLINK_LOG
  24         tristate "Netfilter LOG over NFNETLINK interface"
  25         default m if NETFILTER_ADVANCED=n
  26         select NETFILTER_NETLINK
  27         help
  28           If this option is enabled, the kernel will include support
  29           for logging packets via NFNETLINK.
  30
  31           This obsoletes the existing ipt_ULOG and ebg_ulog mechanisms,
  32           and is also scheduled to replace the old syslog-based ipt_LOG
  33           and ip6t_LOG modules.
  34
  35 config NF_CONNTRACK
  36         tristate "Netfilter connection tracking support"
  37         default m if NETFILTER_ADVANCED=n
  38         help
  39           Connection tracking keeps a record of what packets have passed
  40           through your machine, in order to figure out how they are related
  41           into connections.
  42
  43           This is required to do Masquerading or other kinds of Network
  44           Address Translation.  It can also be used to enhance packet
  45           filtering (see `Connection state match support' below).
  46
  47           To compile it as a module, choose M here.  If unsure, say N.
  48
  49 if NF_CONNTRACK
  50
  51 config NF_CONNTRACK_MARK
  52         bool  'Connection mark tracking support'
  53         depends on NETFILTER_ADVANCED
  54         help
  55           This option enables support for connection marks, used by the
  56           `CONNMARK' target and `connmark' match. Similar to the mark value
  57           of packets, but this mark value is kept in the conntrack session
  58           instead of the individual packets.
  59
  60 config NF_CONNTRACK_SECMARK
  61         bool  'Connection tracking security mark support'
  62         depends on NETWORK_SECMARK
  63         default m if NETFILTER_ADVANCED=n
  64         help
  65           This option enables security markings to be applied to
  66           connections.  Typically they are copied to connections from
  67           packets using the CONNSECMARK target and copied back from
  68           connections to packets with the same target, with the packets
  69           being originally labeled via SECMARK.
  70
  71           If unsure, say 'N'.
  72
  73 config NF_CONNTRACK_ZONES
  74         bool  'Connection tracking zones'
  75         depends on NETFILTER_ADVANCED
  76         depends on NETFILTER_XT_TARGET_CT
  77         help
  78           This option enables support for connection tracking zones.
  79           Normally, each connection needs to have a unique system wide
  80           identity. Connection tracking zones allow to have multiple
  81           connections using the same identity, as long as they are
  82           contained in different zones.
  83
  84           If unsure, say `N'.
  85
  86 config NF_CONNTRACK_PROCFS
  87         bool "Supply CT list in procfs (OBSOLETE)"
  88         default y
  89         depends on PROC_FS
  90         ---help---
  91         This option enables for the list of known conntrack entries
  92         to be shown in procfs under net/netfilter/nf_conntrack. This
  93         is considered obsolete in favor of using the conntrack(8)
  94         tool which uses Netlink.
  95
  96 config NF_CONNTRACK_EVENTS
  97         bool "Connection tracking events"
  98         depends on NETFILTER_ADVANCED
  99         help
 100           If this option is enabled, the connection tracking code will
 101           provide a notifier chain that can be used by other kernel code
 102           to get notified about changes in the connection tracking state.
 103
 104           If unsure, say `N'.
 105
 106 config NF_CONNTRACK_TIMEOUT
 107         bool  'Connection tracking timeout'
 108         depends on NETFILTER_ADVANCED
 109         help
 110           This option enables support for connection tracking timeout
 111           extension. This allows you to attach timeout policies to flow
 112           via the CT target.
 113
 114           If unsure, say `N'.
 115
 116 config NF_CONNTRACK_TIMESTAMP
 117         bool  'Connection tracking timestamping'
 118         depends on NETFILTER_ADVANCED
 119         help
 120           This option enables support for connection tracking timestamping.
 121           This allows you to store the flow start-time and to obtain
 122           the flow-stop time (once it has been destroyed) via Connection
 123           tracking events.
 124
 125           If unsure, say `N'.
 126
 127 config NF_CT_PROTO_DCCP
 128         tristate 'DCCP protocol connection tracking support (EXPERIMENTAL)'
 129         depends on EXPERIMENTAL
 130         depends on NETFILTER_ADVANCED
 131         default IP_DCCP
 132         help
 133           With this option enabled, the layer 3 independent connection
 134           tracking code will be able to do state tracking on DCCP connections.
 135
 136           If unsure, say 'N'.
 137
 138 config NF_CT_PROTO_GRE
 139         tristate
 140
 141 config NF_CT_PROTO_SCTP
 142         tristate 'SCTP protocol connection tracking support (EXPERIMENTAL)'
 143         depends on EXPERIMENTAL
 144         depends on NETFILTER_ADVANCED
 145         default IP_SCTP
 146         help
 147           With this option enabled, the layer 3 independent connection
 148           tracking code will be able to do state tracking on SCTP connections.
 149
 150           If you want to compile it as a module, say M here and read
 151           <file:Documentation/kbuild/modules.txt>.  If unsure, say `N'.
 152
 153 config NF_CT_PROTO_UDPLITE
 154         tristate 'UDP-Lite protocol connection tracking support'
 155         depends on NETFILTER_ADVANCED
 156         help
 157           With this option enabled, the layer 3 independent connection
 158           tracking code will be able to do state tracking on UDP-Lite
 159           connections.
 160
 161           To compile it as a module, choose M here.  If unsure, say N.
 162
 163 config NF_CONNTRACK_AMANDA
 164         tristate "Amanda backup protocol support"
 165         depends on NETFILTER_ADVANCED
 166         select TEXTSEARCH
 167         select TEXTSEARCH_KMP
 168         help
 169           If you are running the Amanda backup package <http://www.amanda.org/>
 170           on this machine or machines that will be MASQUERADED through this
 171           machine, then you may want to enable this feature.  This allows the
 172           connection tracking and natting code to allow the sub-channels that
 173           Amanda requires for communication of the backup data, messages and
 174           index.
 175
 176           To compile it as a module, choose M here.  If unsure, say N.
 177
 178 config NF_CONNTRACK_FTP
 179         tristate "FTP protocol support"
 180         default m if NETFILTER_ADVANCED=n
 181         help
 182           Tracking FTP connections is problematic: special helpers are
 183           required for tracking them, and doing masquerading and other forms
 184           of Network Address Translation on them.
 185
 186           This is FTP support on Layer 3 independent connection tracking.
 187           Layer 3 independent connection tracking is experimental scheme
 188           which generalize ip_conntrack to support other layer 3 protocols.
 189
 190           To compile it as a module, choose M here.  If unsure, say N.
 191
 192 config NF_CONNTRACK_H323
 193         tristate "H.323 protocol support"
 194         depends on (IPV6 || IPV6=n)
 195         depends on NETFILTER_ADVANCED
 196         help
 197           H.323 is a VoIP signalling protocol from ITU-T. As one of the most
 198           important VoIP protocols, it is widely used by voice hardware and
 199           software including voice gateways, IP phones, Netmeeting, OpenPhone,
 200           Gnomemeeting, etc.
 201
 202           With this module you can support H.323 on a connection tracking/NAT
 203           firewall.
 204
 205           This module supports RAS, Fast Start, H.245 Tunnelling, Call
 206           Forwarding, RTP/RTCP and T.120 based audio, video, fax, chat,
 207           whiteboard, file transfer, etc. For more information, please
 208           visit http://nath323.sourceforge.net/.
 209
 210           To compile it as a module, choose M here.  If unsure, say N.
 211
 212 config NF_CONNTRACK_IRC
 213         tristate "IRC protocol support"
 214         default m if NETFILTER_ADVANCED=n
 215         help
 216           There is a commonly-used extension to IRC called
 217           Direct Client-to-Client Protocol (DCC).  This enables users to send
 218           files to each other, and also chat to each other without the need
 219           of a server.  DCC Sending is used anywhere you send files over IRC,
 220           and DCC Chat is most commonly used by Eggdrop bots.  If you are
 221           using NAT, this extension will enable you to send files and initiate
 222           chats.  Note that you do NOT need this extension to get files or
 223           have others initiate chats, or everything else in IRC.
 224
 225           To compile it as a module, choose M here.  If unsure, say N.
 226
 227 config NF_CONNTRACK_BROADCAST
 228         tristate
 229
 230 config NF_CONNTRACK_NETBIOS_NS
 231         tristate "NetBIOS name service protocol support"
 232         select NF_CONNTRACK_BROADCAST
 233         help
 234           NetBIOS name service requests are sent as broadcast messages from an
 235           unprivileged port and responded to with unicast messages to the
 236           same port. This make them hard to firewall properly because connection
 237           tracking doesn't deal with broadcasts. This helper tracks locally
 238           originating NetBIOS name service requests and the corresponding
 239           responses. It relies on correct IP address configuration, specifically
 240           netmask and broadcast address. When properly configured, the output
 241           of "ip address show" should look similar to this:
 242
 243           $ ip -4 address show eth0
 244           4: eth0: <BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 1000
 245               inet 172.16.2.252/24 brd 172.16.2.255 scope global eth0
 246
 247           To compile it as a module, choose M here.  If unsure, say N.
 248
 249 config NF_CONNTRACK_SNMP
 250         tristate "SNMP service protocol support"
 251         depends on NETFILTER_ADVANCED
 252         select NF_CONNTRACK_BROADCAST
 253         help
 254           SNMP service requests are sent as broadcast messages from an
 255           unprivileged port and responded to with unicast messages to the
 256           same port. This make them hard to firewall properly because connection
 257           tracking doesn't deal with broadcasts. This helper tracks locally
 258           originating SNMP service requests and the corresponding
 259           responses. It relies on correct IP address configuration, specifically
 260           netmask and broadcast address.
 261
 262           To compile it as a module, choose M here.  If unsure, say N.
 263
 264 config NF_CONNTRACK_PPTP
 265         tristate "PPtP protocol support"
 266         depends on NETFILTER_ADVANCED
 267         select NF_CT_PROTO_GRE
 268         help
 269           This module adds support for PPTP (Point to Point Tunnelling
 270           Protocol, RFC2637) connection tracking and NAT.
 271
 272           If you are running PPTP sessions over a stateful firewall or NAT
 273           box, you may want to enable this feature.
 274
 275           Please note that not all PPTP modes of operation are supported yet.
 276           Specifically these limitations exist:
 277             - Blindly assumes that control connections are always established
 278               in PNS->PAC direction. This is a violation of RFC2637.
 279             - Only supports a single call within each session
 280
 281           To compile it as a module, choose M here.  If unsure, say N.
 282
 283 config NF_CONNTRACK_SANE
 284         tristate "SANE protocol support (EXPERIMENTAL)"
 285         depends on EXPERIMENTAL
 286         depends on NETFILTER_ADVANCED
 287         help
 288           SANE is a protocol for remote access to scanners as implemented
 289           by the 'saned' daemon. Like FTP, it uses separate control and
 290           data connections.
 291
 292           With this module you can support SANE on a connection tracking
 293           firewall.
 294
 295           To compile it as a module, choose M here.  If unsure, say N.
 296
 297 config NF_CONNTRACK_SIP
 298         tristate "SIP protocol support"
 299         default m if NETFILTER_ADVANCED=n
 300         help
 301           SIP is an application-layer control protocol that can establish,
 302           modify, and terminate multimedia sessions (conferences) such as
 303           Internet telephony calls. With the ip_conntrack_sip and
 304           the nf_nat_sip modules you can support the protocol on a connection
 305           tracking/NATing firewall.
 306
 307           To compile it as a module, choose M here.  If unsure, say N.
 308
 309 config NF_CONNTRACK_TFTP
 310         tristate "TFTP protocol support"
 311         depends on NETFILTER_ADVANCED
 312         help
 313           TFTP connection tracking helper, this is required depending
 314           on how restrictive your ruleset is.
 315           If you are using a tftp client behind -j SNAT or -j MASQUERADING
 316           you will need this.
 317
 318           To compile it as a module, choose M here.  If unsure, say N.
 319
 320 config NF_CT_NETLINK
 321         tristate 'Connection tracking netlink interface'
 322         select NETFILTER_NETLINK
 323         default m if NETFILTER_ADVANCED=n
 324         help
 325           This option enables support for a netlink-based userspace interface
 326
 327 config NF_CT_NETLINK_TIMEOUT
 328         tristate  'Connection tracking timeout tuning via Netlink'
 329         select NETFILTER_NETLINK
 330         depends on NETFILTER_ADVANCED
 331         help
 332           This option enables support for connection tracking timeout
 333           fine-grain tuning. This allows you to attach specific timeout
 334           policies to flows, instead of using the global timeout policy.
 335
 336           If unsure, say `N'.
 337
 338 config NF_CT_NETLINK_HELPER
 339         tristate 'Connection tracking helpers in user-space via Netlink'
 340         select NETFILTER_NETLINK
 341         depends on NF_CT_NETLINK
 342         depends on NETFILTER_NETLINK_QUEUE
 343         depends on NETFILTER_NETLINK_QUEUE_CT
 344         depends on NETFILTER_ADVANCED
 345         help
 346           This option enables the user-space connection tracking helpers
 347           infrastructure.
 348
 349           If unsure, say `N'.
 350
 351 config NETFILTER_NETLINK_QUEUE_CT
 352         bool "NFQUEUE integration with Connection Tracking"
 353         default n
 354         depends on NETFILTER_NETLINK_QUEUE
 355         help
 356           If this option is enabled, NFQUEUE can include Connection Tracking
 357           information together with the packet is the enqueued via NFNETLINK.
 358
 359 config NF_NAT
 360         tristate
 361
 362 config NF_NAT_NEEDED
 363         bool
 364         depends on NF_NAT
 365         default y
 366
 367 config NF_NAT_PROTO_DCCP
 368         tristate
 369         depends on NF_NAT && NF_CT_PROTO_DCCP
 370         default NF_NAT && NF_CT_PROTO_DCCP
 371
 372 config NF_NAT_PROTO_UDPLITE
 373         tristate
 374         depends on NF_NAT && NF_CT_PROTO_UDPLITE
 375         default NF_NAT && NF_CT_PROTO_UDPLITE
 376
 377 config NF_NAT_PROTO_SCTP
 378         tristate
 379         default NF_NAT && NF_CT_PROTO_SCTP
 380         depends on NF_NAT && NF_CT_PROTO_SCTP
 381         select LIBCRC32C
 382
 383 config NF_NAT_AMANDA
 384         tristate
 385         depends on NF_CONNTRACK && NF_NAT
 386         default NF_NAT && NF_CONNTRACK_AMANDA
 387
 388 config NF_NAT_FTP
 389         tristate
 390         depends on NF_CONNTRACK && NF_NAT
 391         default NF_NAT && NF_CONNTRACK_FTP
 392
 393 config NF_NAT_IRC
 394         tristate
 395         depends on NF_CONNTRACK && NF_NAT
 396         default NF_NAT && NF_CONNTRACK_IRC
 397
 398 config NF_NAT_SIP
 399         tristate
 400         depends on NF_CONNTRACK && NF_NAT
 401         default NF_NAT && NF_CONNTRACK_SIP
 402
 403 config NF_NAT_TFTP
 404         tristate
 405         depends on NF_CONNTRACK && NF_NAT
 406         default NF_NAT && NF_CONNTRACK_TFTP
 407
 408 endif # NF_CONNTRACK
 409
 410 # transparent proxy support
 411 config NETFILTER_TPROXY
 412         tristate "Transparent proxying support (EXPERIMENTAL)"
 413         depends on EXPERIMENTAL
 414         depends on IP_NF_MANGLE
 415         depends on NETFILTER_ADVANCED
 416         help
 417           This option enables transparent proxying support, that is,
 418           support for handling non-locally bound IPv4 TCP and UDP sockets.
 419           For it to work you will have to configure certain iptables rules
 420           and use policy routing. For more information on how to set it up
 421           see Documentation/networking/tproxy.txt.
 422
 423           To compile it as a module, choose M here.  If unsure, say N.
 424
 425 config NETFILTER_XTABLES
 426         tristate "Netfilter Xtables support (required for ip_tables)"
 427         default m if NETFILTER_ADVANCED=n
 428         help
 429           This is required if you intend to use any of ip_tables,
 430           ip6_tables or arp_tables.
 431
 432 if NETFILTER_XTABLES
 433
 434 comment "Xtables combined modules"
 435
 436 config NETFILTER_XT_MARK
 437         tristate 'nfmark target and match support'
 438         default m if NETFILTER_ADVANCED=n
 439         ---help---
 440         This option adds the "MARK" target and "mark" match.
 441
 442         Netfilter mark matching allows you to match packets based on the
 443         "nfmark" value in the packet.
 444         The target allows you to create rules in the "mangle" table which alter
 445         the netfilter mark (nfmark) field associated with the packet.
 446
 447         Prior to routing, the nfmark can influence the routing method (see
 448         "Use netfilter MARK value as routing key") and can also be used by
 449         other subsystems to change their behavior.
 450
 451 config NETFILTER_XT_CONNMARK
 452         tristate 'ctmark target and match support'
 453         depends on NF_CONNTRACK
 454         depends on NETFILTER_ADVANCED
 455         select NF_CONNTRACK_MARK
 456         ---help---
 457         This option adds the "CONNMARK" target and "connmark" match.
 458
 459         Netfilter allows you to store a mark value per connection (a.k.a.
 460         ctmark), similarly to the packet mark (nfmark). Using this
 461         target and match, you can set and match on this mark.
 462
 463 config NETFILTER_XT_SET
 464         tristate 'set target and match support'
 465         depends on IP_SET
 466         depends on NETFILTER_ADVANCED
 467         help
 468           This option adds the "SET" target and "set" match.
 469
 470           Using this target and match, you can add/delete and match
 471           elements in the sets created by ipset(8).
 472
 473           To compile it as a module, choose M here.  If unsure, say N.
 474
 475 # alphabetically ordered list of targets
 476
 477 comment "Xtables targets"
 478
 479 config NETFILTER_XT_TARGET_AUDIT
 480         tristate "AUDIT target support"
 481         depends on AUDIT
 482         depends on NETFILTER_ADVANCED
 483         ---help---
 484           This option adds a 'AUDIT' target, which can be used to create
 485           audit records for packets dropped/accepted.
 486
 487           To compileit as a module, choose M here. If unsure, say N.
 488
 489 config NETFILTER_XT_TARGET_CHECKSUM
 490         tristate "CHECKSUM target support"
 491         depends on IP_NF_MANGLE || IP6_NF_MANGLE
 492         depends on NETFILTER_ADVANCED
 493         ---help---
 494           This option adds a `CHECKSUM' target, which can be used in the iptables mangle
 495           table.
 496
 497           You can use this target to compute and fill in the checksum in
 498           a packet that lacks a checksum.  This is particularly useful,
 499           if you need to work around old applications such as dhcp clients,
 500           that do not work well with checksum offloads, but don't want to disable
 501           checksum offload in your device.
 502
 503           To compile it as a module, choose M here.  If unsure, say N.
 504
 505 config NETFILTER_XT_TARGET_CLASSIFY
 506         tristate '"CLASSIFY" target support'
 507         depends on NETFILTER_ADVANCED
 508         help
 509           This option adds a `CLASSIFY' target, which enables the user to set
 510           the priority of a packet. Some qdiscs can use this value for
 511           classification, among these are:
 512
 513           atm, cbq, dsmark, pfifo_fast, htb, prio
 514
 515           To compile it as a module, choose M here.  If unsure, say N.
 516
 517 config NETFILTER_XT_TARGET_CONNMARK
 518         tristate  '"CONNMARK" target support'
 519         depends on NF_CONNTRACK
 520         depends on NETFILTER_ADVANCED
 521         select NETFILTER_XT_CONNMARK
 522         ---help---
 523         This is a backwards-compat option for the user's convenience
 524         (e.g. when running oldconfig). It selects
 525         CONFIG_NETFILTER_XT_CONNMARK (combined connmark/CONNMARK module).
 526
 527 config NETFILTER_XT_TARGET_CONNSECMARK
 528         tristate '"CONNSECMARK" target support'
 529         depends on NF_CONNTRACK && NF_CONNTRACK_SECMARK
 530         default m if NETFILTER_ADVANCED=n
 531         help
 532           The CONNSECMARK target copies security markings from packets
 533           to connections, and restores security markings from connections
 534           to packets (if the packets are not already marked).  This would
 535           normally be used in conjunction with the SECMARK target.
 536
 537           To compile it as a module, choose M here.  If unsure, say N.
 538
 539 config NETFILTER_XT_TARGET_CT
 540         tristate '"CT" target support'
 541         depends on NF_CONNTRACK
 542         depends on IP_NF_RAW || IP6_NF_RAW
 543         depends on NETFILTER_ADVANCED
 544         help
 545           This options adds a `CT' target, which allows to specify initial
 546           connection tracking parameters like events to be delivered and
 547           the helper to be used.
 548
 549           To compile it as a module, choose M here.  If unsure, say N.
 550
 551 config NETFILTER_XT_TARGET_DSCP
 552         tristate '"DSCP" and "TOS" target support'
 553         depends on IP_NF_MANGLE || IP6_NF_MANGLE
 554         depends on NETFILTER_ADVANCED
 555         help
 556           This option adds a `DSCP' target, which allows you to manipulate
 557           the IPv4/IPv6 header DSCP field (differentiated services codepoint).
 558
 559           The DSCP field can have any value between 0x0 and 0x3f inclusive.
 560
 561           It also adds the "TOS" target, which allows you to create rules in
 562           the "mangle" table which alter the Type Of Service field of an IPv4
 563           or the Priority field of an IPv6 packet, prior to routing.
 564
 565           To compile it as a module, choose M here.  If unsure, say N.
 566
 567 config NETFILTER_XT_TARGET_HL
 568         tristate '"HL" hoplimit target support'
 569         depends on IP_NF_MANGLE || IP6_NF_MANGLE
 570         depends on NETFILTER_ADVANCED
 571         ---help---
 572         This option adds the "HL" (for IPv6) and "TTL" (for IPv4)
 573         targets, which enable the user to change the
 574         hoplimit/time-to-live value of the IP header.
 575
 576         While it is safe to decrement the hoplimit/TTL value, the
 577         modules also allow to increment and set the hoplimit value of
 578         the header to arbitrary values. This is EXTREMELY DANGEROUS
 579         since you can easily create immortal packets that loop
 580         forever on the network.
 581
 582 config NETFILTER_XT_TARGET_HMARK
 583         tristate '"HMARK" target support'
 584         depends on (IP6_NF_IPTABLES || IP6_NF_IPTABLES=n)
 585         depends on NETFILTER_ADVANCED
 586         ---help---
 587         This option adds the "HMARK" target.
 588
 589         The target allows you to create rules in the "raw" and "mangle" tables
 590         which set the skbuff mark by means of hash calculation within a given
 591         range. The nfmark can influence the routing method (see "Use netfilter
 592         MARK value as routing key") and can also be used by other subsystems to
 593         change their behaviour.
 594
 595         To compile it as a module, choose M here. If unsure, say N.
 596
 597 config NETFILTER_XT_TARGET_IDLETIMER
 598         tristate  "IDLETIMER target support"
 599         depends on NETFILTER_ADVANCED
 600         help
 601
 602           This option adds the `IDLETIMER' target.  Each matching packet
 603           resets the timer associated with label specified when the rule is
 604           added.  When the timer expires, it triggers a sysfs notification.
 605           The remaining time for expiration can be read via sysfs.
 606
 607           To compile it as a module, choose M here.  If unsure, say N.
 608
 609 config NETFILTER_XT_TARGET_LED
 610         tristate '"LED" target support'
 611         depends on LEDS_CLASS && LEDS_TRIGGERS
 612         depends on NETFILTER_ADVANCED
 613         help
 614           This option adds a `LED' target, which allows you to blink LEDs in
 615           response to particular packets passing through your machine.
 616
 617           This can be used to turn a spare LED into a network activity LED,
 618           which only flashes in response to FTP transfers, for example.  Or
 619           you could have an LED which lights up for a minute or two every time
 620           somebody connects to your machine via SSH.
 621
 622           You will need support for the "led" class to make this work.
 623
 624           To create an LED trigger for incoming SSH traffic:
 625             iptables -A INPUT -p tcp --dport 22 -j LED --led-trigger-id ssh --led-delay 1000
 626
 627           Then attach the new trigger to an LED on your system:
 628             echo netfilter-ssh > /sys/class/leds/<ledname>/trigger
 629
 630           For more information on the LEDs available on your system, see
 631           Documentation/leds/leds-class.txt
 632
 633 config NETFILTER_XT_TARGET_LOG
 634         tristate "LOG target support"
 635         default m if NETFILTER_ADVANCED=n
 636         help
 637           This option adds a `LOG' target, which allows you to create rules in
 638           any iptables table which records the packet header to the syslog.
 639
 640           To compile it as a module, choose M here.  If unsure, say N.
 641
 642 config NETFILTER_XT_TARGET_MARK
 643         tristate '"MARK" target support'
 644         depends on NETFILTER_ADVANCED
 645         select NETFILTER_XT_MARK
 646         ---help---
 647         This is a backwards-compat option for the user's convenience
 648         (e.g. when running oldconfig). It selects
 649         CONFIG_NETFILTER_XT_MARK (combined mark/MARK module).
 650
 651 config NETFILTER_XT_TARGET_NETMAP
 652         tristate '"NETMAP" target support'
 653         depends on NF_NAT
 654         ---help---
 655         NETMAP is an implementation of static 1:1 NAT mapping of network
 656         addresses. It maps the network address part, while keeping the host
 657         address part intact.
 658
 659         To compile it as a module, choose M here. If unsure, say N.
 660
 661 config NETFILTER_XT_TARGET_NFLOG
 662         tristate '"NFLOG" target support'
 663         default m if NETFILTER_ADVANCED=n
 664         select NETFILTER_NETLINK_LOG
 665         help
 666           This option enables the NFLOG target, which allows to LOG
 667           messages through nfnetlink_log.
 668
 669           To compile it as a module, choose M here.  If unsure, say N.
 670
 671 config NETFILTER_XT_TARGET_NFQUEUE
 672         tristate '"NFQUEUE" target Support'
 673         depends on NETFILTER_ADVANCED
 674         select NETFILTER_NETLINK_QUEUE
 675         help
 676           This target replaced the old obsolete QUEUE target.
 677
 678           As opposed to QUEUE, it supports 65535 different queues,
 679           not just one.
 680
 681           To compile it as a module, choose M here.  If unsure, say N.
 682
 683 config NETFILTER_XT_TARGET_NOTRACK
 684         tristate  '"NOTRACK" target support (DEPRECATED)'
 685         depends on NF_CONNTRACK
 686         depends on IP_NF_RAW || IP6_NF_RAW
 687         depends on NETFILTER_ADVANCED
 688         select NETFILTER_XT_TARGET_CT
 689
 690 config NETFILTER_XT_TARGET_RATEEST
 691         tristate '"RATEEST" target support'
 692         depends on NETFILTER_ADVANCED
 693         help
 694           This option adds a `RATEEST' target, which allows to measure
 695           rates similar to TC estimators. The `rateest' match can be
 696           used to match on the measured rates.
 697
 698           To compile it as a module, choose M here.  If unsure, say N.
 699
 700 config NETFILTER_XT_TARGET_REDIRECT
 701         tristate "REDIRECT target support"
 702         depends on NF_NAT
 703         ---help---
 704         REDIRECT is a special case of NAT: all incoming connections are
 705         mapped onto the incoming interface's address, causing the packets to
 706         come to the local machine instead of passing through. This is
 707         useful for transparent proxies.
 708
 709         To compile it as a module, choose M here. If unsure, say N.
 710
 711 config NETFILTER_XT_TARGET_TEE
 712         tristate '"TEE" - packet cloning to alternate destination'
 713         depends on NETFILTER_ADVANCED
 714         depends on (IPV6 || IPV6=n)
 715         depends on !NF_CONNTRACK || NF_CONNTRACK
 716         ---help---
 717         This option adds a "TEE" target with which a packet can be cloned and
 718         this clone be rerouted to another nexthop.
 719
 720 config NETFILTER_XT_TARGET_TPROXY
 721         tristate '"TPROXY" target support (EXPERIMENTAL)'
 722         depends on EXPERIMENTAL
 723         depends on NETFILTER_TPROXY
 724         depends on NETFILTER_XTABLES
 725         depends on NETFILTER_ADVANCED
 726         select NF_DEFRAG_IPV4
 727         select NF_DEFRAG_IPV6 if IP6_NF_IPTABLES
 728         help
 729           This option adds a `TPROXY' target, which is somewhat similar to
 730           REDIRECT.  It can only be used in the mangle table and is useful
 731           to redirect traffic to a transparent proxy.  It does _not_ depend
 732           on Netfilter connection tracking and NAT, unlike REDIRECT.
 733
 734           To compile it as a module, choose M here.  If unsure, say N.
 735
 736 config NETFILTER_XT_TARGET_TRACE
 737         tristate  '"TRACE" target support'
 738         depends on IP_NF_RAW || IP6_NF_RAW
 739         depends on NETFILTER_ADVANCED
 740         help
 741           The TRACE target allows you to mark packets so that the kernel
 742           will log every rule which match the packets as those traverse
 743           the tables, chains, rules.
 744
 745           If you want to compile it as a module, say M here and read
 746           <file:Documentation/kbuild/modules.txt>.  If unsure, say `N'.
 747
 748 config NETFILTER_XT_TARGET_SECMARK
 749         tristate '"SECMARK" target support'
 750         depends on NETWORK_SECMARK
 751         default m if NETFILTER_ADVANCED=n
 752         help
 753           The SECMARK target allows security marking of network
 754           packets, for use with security subsystems.
 755
 756           To compile it as a module, choose M here.  If unsure, say N.
 757
 758 config NETFILTER_XT_TARGET_TCPMSS
 759         tristate '"TCPMSS" target support'
 760         depends on (IPV6 || IPV6=n)
 761         default m if NETFILTER_ADVANCED=n
 762         ---help---
 763           This option adds a `TCPMSS' target, which allows you to alter the
 764           MSS value of TCP SYN packets, to control the maximum size for that
 765           connection (usually limiting it to your outgoing interface's MTU
 766           minus 40).
 767
 768           This is used to overcome criminally braindead ISPs or servers which
 769           block ICMP Fragmentation Needed packets.  The symptoms of this
 770           problem are that everything works fine from your Linux
 771           firewall/router, but machines behind it can never exchange large
 772           packets:
 773                 1) Web browsers connect, then hang with no data received.
 774                 2) Small mail works fine, but large emails hang.
 775                 3) ssh works fine, but scp hangs after initial handshaking.
 776
 777           Workaround: activate this option and add a rule to your firewall
 778           configuration like:
 779
 780           iptables -A FORWARD -p tcp --tcp-flags SYN,RST SYN \
 781                          -j TCPMSS --clamp-mss-to-pmtu
 782
 783           To compile it as a module, choose M here.  If unsure, say N.
 784
 785 config NETFILTER_XT_TARGET_TCPOPTSTRIP
 786         tristate '"TCPOPTSTRIP" target support (EXPERIMENTAL)'
 787         depends on EXPERIMENTAL
 788         depends on IP_NF_MANGLE || IP6_NF_MANGLE
 789         depends on NETFILTER_ADVANCED
 790         help
 791           This option adds a "TCPOPTSTRIP" target, which allows you to strip
 792           TCP options from TCP packets.
 793
 794 # alphabetically ordered list of matches
 795
 796 comment "Xtables matches"
 797
 798 config NETFILTER_XT_MATCH_ADDRTYPE
 799         tristate '"addrtype" address type match support'
 800         depends on NETFILTER_ADVANCED
 801         ---help---
 802           This option allows you to match what routing thinks of an address,
 803           eg. UNICAST, LOCAL, BROADCAST, ...
 804
 805           If you want to compile it as a module, say M here and read
 806           <file:Documentation/kbuild/modules.txt>.  If unsure, say `N'.
 807
 808 config NETFILTER_XT_MATCH_CLUSTER
 809         tristate '"cluster" match support'
 810         depends on NF_CONNTRACK
 811         depends on NETFILTER_ADVANCED
 812         ---help---
 813           This option allows you to build work-load-sharing clusters of
 814           network servers/stateful firewalls without having a dedicated
 815           load-balancing router/server/switch. Basically, this match returns
 816           true when the packet must be handled by this cluster node. Thus,
 817           all nodes see all packets and this match decides which node handles
 818           what packets. The work-load sharing algorithm is based on source
 819           address hashing.
 820
 821           If you say Y or M here, try `iptables -m cluster --help` for
 822           more information.
 823
 824 config NETFILTER_XT_MATCH_COMMENT
 825         tristate  '"comment" match support'
 826         depends on NETFILTER_ADVANCED
 827         help
 828           This option adds a `comment' dummy-match, which allows you to put
 829           comments in your iptables ruleset.
 830
 831           If you want to compile it as a module, say M here and read
 832           <file:Documentation/kbuild/modules.txt>.  If unsure, say `N'.
 833
 834 config NETFILTER_XT_MATCH_CONNBYTES
 835         tristate  '"connbytes" per-connection counter match support'
 836         depends on NF_CONNTRACK
 837         depends on NETFILTER_ADVANCED
 838         help
 839           This option adds a `connbytes' match, which allows you to match the
 840           number of bytes and/or packets for each direction within a connection.
 841
 842           If you want to compile it as a module, say M here and read
 843           <file:Documentation/kbuild/modules.txt>.  If unsure, say `N'.
 844
 845 config NETFILTER_XT_MATCH_CONNLIMIT
 846         tristate '"connlimit" match support"'
 847         depends on NF_CONNTRACK
 848         depends on NETFILTER_ADVANCED
 849         ---help---
 850           This match allows you to match against the number of parallel
 851           connections to a server per client IP address (or address block).
 852
 853 config NETFILTER_XT_MATCH_CONNMARK
 854         tristate  '"connmark" connection mark match support'
 855         depends on NF_CONNTRACK
 856         depends on NETFILTER_ADVANCED
 857         select NETFILTER_XT_CONNMARK
 858         ---help---
 859         This is a backwards-compat option for the user's convenience
 860         (e.g. when running oldconfig). It selects
 861         CONFIG_NETFILTER_XT_CONNMARK (combined connmark/CONNMARK module).
 862
 863 config NETFILTER_XT_MATCH_CONNTRACK
 864         tristate '"conntrack" connection tracking match support'
 865         depends on NF_CONNTRACK
 866         default m if NETFILTER_ADVANCED=n
 867         help
 868           This is a general conntrack match module, a superset of the state match.
 869
 870           It allows matching on additional conntrack information, which is
 871           useful in complex configurations, such as NAT gateways with multiple
 872           internet links or tunnels.
 873
 874           To compile it as a module, choose M here.  If unsure, say N.
 875
 876 config NETFILTER_XT_MATCH_CPU
 877         tristate '"cpu" match support'
 878         depends on NETFILTER_ADVANCED
 879         help
 880           CPU matching allows you to match packets based on the CPU
 881           currently handling the packet.
 882
 883           To compile it as a module, choose M here.  If unsure, say N.
 884
 885 config NETFILTER_XT_MATCH_DCCP
 886         tristate '"dccp" protocol match support'
 887         depends on NETFILTER_ADVANCED
 888         default IP_DCCP
 889         help
 890           With this option enabled, you will be able to use the iptables
 891           `dccp' match in order to match on DCCP source/destination ports
 892           and DCCP flags.
 893
 894           If you want to compile it as a module, say M here and read
 895           <file:Documentation/kbuild/modules.txt>.  If unsure, say `N'.
 896
 897 config NETFILTER_XT_MATCH_DEVGROUP
 898         tristate '"devgroup" match support'
 899         depends on NETFILTER_ADVANCED
 900         help
 901           This options adds a `devgroup' match, which allows to match on the
 902           device group a network device is assigned to.
 903
 904           To compile it as a module, choose M here.  If unsure, say N.
 905
 906 config NETFILTER_XT_MATCH_DSCP
 907         tristate '"dscp" and "tos" match support'
 908         depends on NETFILTER_ADVANCED
 909         help
 910           This option adds a `DSCP' match, which allows you to match against
 911           the IPv4/IPv6 header DSCP field (differentiated services codepoint).
 912
 913           The DSCP field can have any value between 0x0 and 0x3f inclusive.
 914
 915           It will also add a "tos" match, which allows you to match packets
 916           based on the Type Of Service fields of the IPv4 packet (which share
 917           the same bits as DSCP).
 918
 919           To compile it as a module, choose M here.  If unsure, say N.
 920
 921 config NETFILTER_XT_MATCH_ECN
 922         tristate '"ecn" match support'
 923         depends on NETFILTER_ADVANCED
 924         ---help---
 925         This option adds an "ECN" match, which allows you to match against
 926         the IPv4 and TCP header ECN fields.
 927
 928         To compile it as a module, choose M here. If unsure, say N.
 929
 930 config NETFILTER_XT_MATCH_ESP
 931         tristate '"esp" match support'
 932         depends on NETFILTER_ADVANCED
 933         help
 934           This match extension allows you to match a range of SPIs
 935           inside ESP header of IPSec packets.
 936
 937           To compile it as a module, choose M here.  If unsure, say N.
 938
 939 config NETFILTER_XT_MATCH_HASHLIMIT
 940         tristate '"hashlimit" match support'
 941         depends on (IP6_NF_IPTABLES || IP6_NF_IPTABLES=n)
 942         depends on NETFILTER_ADVANCED
 943         help
 944           This option adds a `hashlimit' match.
 945
 946           As opposed to `limit', this match dynamically creates a hash table
 947           of limit buckets, based on your selection of source/destination
 948           addresses and/or ports.
 949
 950           It enables you to express policies like `10kpps for any given
 951           destination address' or `500pps from any given source address'
 952           with a single rule.
 953
 954 config NETFILTER_XT_MATCH_HELPER
 955         tristate '"helper" match support'
 956         depends on NF_CONNTRACK
 957         depends on NETFILTER_ADVANCED
 958         help
 959           Helper matching allows you to match packets in dynamic connections
 960           tracked by a conntrack-helper, ie. ip_conntrack_ftp
 961
 962           To compile it as a module, choose M here.  If unsure, say Y.
 963
 964 config NETFILTER_XT_MATCH_HL
 965         tristate '"hl" hoplimit/TTL match support'
 966         depends on NETFILTER_ADVANCED
 967         ---help---
 968         HL matching allows you to match packets based on the hoplimit
 969         in the IPv6 header, or the time-to-live field in the IPv4
 970         header of the packet.
 971
 972 config NETFILTER_XT_MATCH_IPRANGE
 973         tristate '"iprange" address range match support'
 974         depends on NETFILTER_ADVANCED
 975         ---help---
 976         This option adds a "iprange" match, which allows you to match based on
 977         an IP address range. (Normal iptables only matches on single addresses
 978         with an optional mask.)
 979
 980         If unsure, say M.
 981
 982 config NETFILTER_XT_MATCH_IPVS
 983         tristate '"ipvs" match support'
 984         depends on IP_VS
 985         depends on NETFILTER_ADVANCED
 986         depends on NF_CONNTRACK
 987         help
 988           This option allows you to match against IPVS properties of a packet.
 989
 990           If unsure, say N.
 991
 992 config NETFILTER_XT_MATCH_LENGTH
 993         tristate '"length" match support'
 994         depends on NETFILTER_ADVANCED
 995         help
 996           This option allows you to match the length of a packet against a
 997           specific value or range of values.
 998
 999           To compile it as a module, choose M here.  If unsure, say N.
1000
1001 config NETFILTER_XT_MATCH_LIMIT
1002         tristate '"limit" match support'
1003         depends on NETFILTER_ADVANCED
1004         help
1005           limit matching allows you to control the rate at which a rule can be
1006           matched: mainly useful in combination with the LOG target ("LOG
1007           target support", below) and to avoid some Denial of Service attacks.
1008
1009           To compile it as a module, choose M here.  If unsure, say N.
1010
1011 config NETFILTER_XT_MATCH_MAC
1012         tristate '"mac" address match support'
1013         depends on NETFILTER_ADVANCED
1014         help
1015           MAC matching allows you to match packets based on the source
1016           Ethernet address of the packet.
1017
1018           To compile it as a module, choose M here.  If unsure, say N.
1019
1020 config NETFILTER_XT_MATCH_MARK
1021         tristate '"mark" match support'
1022         depends on NETFILTER_ADVANCED
1023         select NETFILTER_XT_MARK
1024         ---help---
1025         This is a backwards-compat option for the user's convenience
1026         (e.g. when running oldconfig). It selects
1027         CONFIG_NETFILTER_XT_MARK (combined mark/MARK module).
1028
1029 config NETFILTER_XT_MATCH_MULTIPORT
1030         tristate '"multiport" Multiple port match support'
1031         depends on NETFILTER_ADVANCED
1032         help
1033           Multiport matching allows you to match TCP or UDP packets based on
1034           a series of source or destination ports: normally a rule can only
1035           match a single range of ports.
1036
1037           To compile it as a module, choose M here.  If unsure, say N.
1038
1039 config NETFILTER_XT_MATCH_NFACCT
1040         tristate '"nfacct" match support'
1041         depends on NETFILTER_ADVANCED
1042         select NETFILTER_NETLINK_ACCT
1043         help
1044           This option allows you to use the extended accounting through
1045           nfnetlink_acct.
1046
1047           To compile it as a module, choose M here.  If unsure, say N.
1048
1049 config NETFILTER_XT_MATCH_OSF
1050         tristate '"osf" Passive OS fingerprint match'
1051         depends on NETFILTER_ADVANCED && NETFILTER_NETLINK
1052         help
1053           This option selects the Passive OS Fingerprinting match module
1054           that allows to passively match the remote operating system by
1055           analyzing incoming TCP SYN packets.
1056
1057           Rules and loading software can be downloaded from
1058           http://www.ioremap.net/projects/osf
1059
1060           To compile it as a module, choose M here.  If unsure, say N.
1061
1062 config NETFILTER_XT_MATCH_OWNER
1063         tristate '"owner" match support'
1064         depends on NETFILTER_ADVANCED
1065         ---help---
1066         Socket owner matching allows you to match locally-generated packets
1067         based on who created the socket: the user or group. It is also
1068         possible to check whether a socket actually exists.
1069
1070 config NETFILTER_XT_MATCH_POLICY
1071         tristate 'IPsec "policy" match support'
1072         depends on XFRM
1073         default m if NETFILTER_ADVANCED=n
1074         help
1075           Policy matching allows you to match packets based on the
1076           IPsec policy that was used during decapsulation/will
1077           be used during encapsulation.
1078
1079           To compile it as a module, choose M here.  If unsure, say N.
1080
1081 config NETFILTER_XT_MATCH_PHYSDEV
1082         tristate '"physdev" match support'
1083         depends on BRIDGE && BRIDGE_NETFILTER
1084         depends on NETFILTER_ADVANCED
1085         help
1086           Physdev packet matching matches against the physical bridge ports
1087           the IP packet arrived on or will leave by.
1088
1089           To compile it as a module, choose M here.  If unsure, say N.
1090
1091 config NETFILTER_XT_MATCH_PKTTYPE
1092         tristate '"pkttype" packet type match support'
1093         depends on NETFILTER_ADVANCED
1094         help
1095           Packet type matching allows you to match a packet by
1096           its "class", eg. BROADCAST, MULTICAST, ...
1097
1098           Typical usage:
1099           iptables -A INPUT -m pkttype --pkt-type broadcast -j LOG
1100
1101           To compile it as a module, choose M here.  If unsure, say N.
1102
1103 config NETFILTER_XT_MATCH_QUOTA
1104         tristate '"quota" match support'
1105         depends on NETFILTER_ADVANCED
1106         help
1107           This option adds a `quota' match, which allows to match on a
1108           byte counter.
1109
1110           If you want to compile it as a module, say M here and read
1111           <file:Documentation/kbuild/modules.txt>.  If unsure, say `N'.
1112
1113 config NETFILTER_XT_MATCH_RATEEST
1114         tristate '"rateest" match support'
1115         depends on NETFILTER_ADVANCED
1116         select NETFILTER_XT_TARGET_RATEEST
1117         help
1118           This option adds a `rateest' match, which allows to match on the
1119           rate estimated by the RATEEST target.
1120
1121           To compile it as a module, choose M here.  If unsure, say N.
1122
1123 config NETFILTER_XT_MATCH_REALM
1124         tristate  '"realm" match support'
1125         depends on NETFILTER_ADVANCED
1126         select IP_ROUTE_CLASSID
1127         help
1128           This option adds a `realm' match, which allows you to use the realm
1129           key from the routing subsystem inside iptables.
1130
1131           This match pretty much resembles the CONFIG_NET_CLS_ROUTE4 option
1132           in tc world.
1133
1134           If you want to compile it as a module, say M here and read
1135           <file:Documentation/kbuild/modules.txt>.  If unsure, say `N'.
1136
1137 config NETFILTER_XT_MATCH_RECENT
1138         tristate '"recent" match support'
1139         depends on NETFILTER_ADVANCED
1140         ---help---
1141         This match is used for creating one or many lists of recently
1142         used addresses and then matching against that/those list(s).
1143
1144         Short options are available by using 'iptables -m recent -h'
1145         Official Website: <http://snowman.net/projects/ipt_recent/>
1146
1147 config NETFILTER_XT_MATCH_SCTP
1148         tristate  '"sctp" protocol match support (EXPERIMENTAL)'
1149         depends on EXPERIMENTAL
1150         depends on NETFILTER_ADVANCED
1151         default IP_SCTP
1152         help
1153           With this option enabled, you will be able to use the
1154           `sctp' match in order to match on SCTP source/destination ports
1155           and SCTP chunk types.
1156
1157           If you want to compile it as a module, say M here and read
1158           <file:Documentation/kbuild/modules.txt>.  If unsure, say `N'.
1159
1160 config NETFILTER_XT_MATCH_SOCKET
1161         tristate '"socket" match support (EXPERIMENTAL)'
1162         depends on EXPERIMENTAL
1163         depends on NETFILTER_TPROXY
1164         depends on NETFILTER_XTABLES
1165         depends on NETFILTER_ADVANCED
1166         depends on !NF_CONNTRACK || NF_CONNTRACK
1167         select NF_DEFRAG_IPV4
1168         select NF_DEFRAG_IPV6 if IP6_NF_IPTABLES
1169         help
1170           This option adds a `socket' match, which can be used to match
1171           packets for which a TCP or UDP socket lookup finds a valid socket.
1172           It can be used in combination with the MARK target and policy
1173           routing to implement full featured non-locally bound sockets.
1174
1175           To compile it as a module, choose M here.  If unsure, say N.
1176
1177 config NETFILTER_XT_MATCH_STATE
1178         tristate '"state" match support'
1179         depends on NF_CONNTRACK
1180         default m if NETFILTER_ADVANCED=n
1181         help
1182           Connection state matching allows you to match packets based on their
1183           relationship to a tracked connection (ie. previous packets).  This
1184           is a powerful tool for packet classification.
1185
1186           To compile it as a module, choose M here.  If unsure, say N.
1187
1188 config NETFILTER_XT_MATCH_STATISTIC
1189         tristate '"statistic" match support'
1190         depends on NETFILTER_ADVANCED
1191         help
1192           This option adds a `statistic' match, which allows you to match
1193           on packets periodically or randomly with a given percentage.
1194
1195           To compile it as a module, choose M here.  If unsure, say N.
1196
1197 config NETFILTER_XT_MATCH_STRING
1198         tristate  '"string" match support'
1199         depends on NETFILTER_ADVANCED
1200         select TEXTSEARCH
1201         select TEXTSEARCH_KMP
1202         select TEXTSEARCH_BM
1203         select TEXTSEARCH_FSM
1204         help
1205           This option adds a `string' match, which allows you to look for
1206           pattern matchings in packets.
1207
1208           To compile it as a module, choose M here.  If unsure, say N.
1209
1210 config NETFILTER_XT_MATCH_TCPMSS
1211         tristate '"tcpmss" match support'
1212         depends on NETFILTER_ADVANCED
1213         help
1214           This option adds a `tcpmss' match, which allows you to examine the
1215           MSS value of TCP SYN packets, which control the maximum packet size
1216           for that connection.
1217
1218           To compile it as a module, choose M here.  If unsure, say N.
1219
1220 config NETFILTER_XT_MATCH_TIME
1221         tristate '"time" match support'
1222         depends on NETFILTER_ADVANCED
1223         ---help---
1224           This option adds a "time" match, which allows you to match based on
1225           the packet arrival time (at the machine which netfilter is running)
1226           on) or departure time/date (for locally generated packets).
1227
1228           If you say Y here, try `iptables -m time --help` for
1229           more information.
1230
1231           If you want to compile it as a module, say M here.
1232           If unsure, say N.
1233
1234 config NETFILTER_XT_MATCH_U32
1235         tristate '"u32" match support'
1236         depends on NETFILTER_ADVANCED
1237         ---help---
1238           u32 allows you to extract quantities of up to 4 bytes from a packet,
1239           AND them with specified masks, shift them by specified amounts and
1240           test whether the results are in any of a set of specified ranges.
1241           The specification of what to extract is general enough to skip over
1242           headers with lengths stored in the packet, as in IP or TCP header
1243           lengths.
1244
1245           Details and examples are in the kernel module source.
1246
1247 endif # NETFILTER_XTABLES
1248
1249 endmenu
1250
1251 source "net/netfilter/ipset/Kconfig"
1252
1253 source "net/netfilter/ipvs/Kconfig"