1 menu "Core Netfilter Configuration"
2 depends on NET && INET && NETFILTER
4 config NETFILTER_INGRESS
5 bool "Netfilter ingress support"
9 This allows you to classify packets from ingress using the Netfilter
12 config NETFILTER_NETLINK
15 config NETFILTER_NETLINK_ACCT
16 tristate "Netfilter NFACCT over NFNETLINK interface"
17 depends on NETFILTER_ADVANCED
18 select NETFILTER_NETLINK
20 If this option is enabled, the kernel will include support
21 for extended accounting via NFNETLINK.
23 config NETFILTER_NETLINK_QUEUE
24 tristate "Netfilter NFQUEUE over NFNETLINK interface"
25 depends on NETFILTER_ADVANCED
26 select NETFILTER_NETLINK
28 If this option is enabled, the kernel will include support
29 for queueing packets via NFNETLINK.
31 config NETFILTER_NETLINK_LOG
32 tristate "Netfilter LOG over NFNETLINK interface"
33 default m if NETFILTER_ADVANCED=n
34 select NETFILTER_NETLINK
36 If this option is enabled, the kernel will include support
37 for logging packets via NFNETLINK.
39 This obsoletes the existing ipt_ULOG and ebg_ulog mechanisms,
40 and is also scheduled to replace the old syslog-based ipt_LOG
44 tristate "Netfilter connection tracking support"
45 default m if NETFILTER_ADVANCED=n
47 Connection tracking keeps a record of what packets have passed
48 through your machine, in order to figure out how they are related
51 This is required to do Masquerading or other kinds of Network
52 Address Translation. It can also be used to enhance packet
53 filtering (see `Connection state match support' below).
55 To compile it as a module, choose M here. If unsure, say N.
61 tristate "Netdev packet logging"
66 config NF_CONNTRACK_MARK
67 bool 'Connection mark tracking support'
68 depends on NETFILTER_ADVANCED
70 This option enables support for connection marks, used by the
71 `CONNMARK' target and `connmark' match. Similar to the mark value
72 of packets, but this mark value is kept in the conntrack session
73 instead of the individual packets.
75 config NF_CONNTRACK_SECMARK
76 bool 'Connection tracking security mark support'
77 depends on NETWORK_SECMARK
78 default m if NETFILTER_ADVANCED=n
80 This option enables security markings to be applied to
81 connections. Typically they are copied to connections from
82 packets using the CONNSECMARK target and copied back from
83 connections to packets with the same target, with the packets
84 being originally labeled via SECMARK.
88 config NF_CONNTRACK_ZONES
89 bool 'Connection tracking zones'
90 depends on NETFILTER_ADVANCED
91 depends on NETFILTER_XT_TARGET_CT
93 This option enables support for connection tracking zones.
94 Normally, each connection needs to have a unique system wide
95 identity. Connection tracking zones allow to have multiple
96 connections using the same identity, as long as they are
97 contained in different zones.
101 config NF_CONNTRACK_PROCFS
102 bool "Supply CT list in procfs (OBSOLETE)"
106 This option enables for the list of known conntrack entries
107 to be shown in procfs under net/netfilter/nf_conntrack. This
108 is considered obsolete in favor of using the conntrack(8)
109 tool which uses Netlink.
111 config NF_CONNTRACK_EVENTS
112 bool "Connection tracking events"
113 depends on NETFILTER_ADVANCED
115 If this option is enabled, the connection tracking code will
116 provide a notifier chain that can be used by other kernel code
117 to get notified about changes in the connection tracking state.
121 config NF_CONNTRACK_TIMEOUT
122 bool 'Connection tracking timeout'
123 depends on NETFILTER_ADVANCED
125 This option enables support for connection tracking timeout
126 extension. This allows you to attach timeout policies to flow
131 config NF_CONNTRACK_TIMESTAMP
132 bool 'Connection tracking timestamping'
133 depends on NETFILTER_ADVANCED
135 This option enables support for connection tracking timestamping.
136 This allows you to store the flow start-time and to obtain
137 the flow-stop time (once it has been destroyed) via Connection
142 config NF_CONNTRACK_LABELS
145 This option enables support for assigning user-defined flag bits
146 to connection tracking entries. It selected by the connlabel match.
148 config NF_CT_PROTO_DCCP
149 bool 'DCCP protocol connection tracking support'
150 depends on NETFILTER_ADVANCED
153 With this option enabled, the layer 3 independent connection
154 tracking code will be able to do state tracking on DCCP connections.
158 config NF_CT_PROTO_GRE
161 config NF_CT_PROTO_SCTP
162 bool 'SCTP protocol connection tracking support'
163 depends on NETFILTER_ADVANCED
167 With this option enabled, the layer 3 independent connection
168 tracking code will be able to do state tracking on SCTP connections.
172 config NF_CT_PROTO_UDPLITE
173 bool 'UDP-Lite protocol connection tracking support'
174 depends on NETFILTER_ADVANCED
177 With this option enabled, the layer 3 independent connection
178 tracking code will be able to do state tracking on UDP-Lite
183 config NF_CONNTRACK_AMANDA
184 tristate "Amanda backup protocol support"
185 depends on NETFILTER_ADVANCED
187 select TEXTSEARCH_KMP
189 If you are running the Amanda backup package <http://www.amanda.org/>
190 on this machine or machines that will be MASQUERADED through this
191 machine, then you may want to enable this feature. This allows the
192 connection tracking and natting code to allow the sub-channels that
193 Amanda requires for communication of the backup data, messages and
196 To compile it as a module, choose M here. If unsure, say N.
198 config NF_CONNTRACK_FTP
199 tristate "FTP protocol support"
200 default m if NETFILTER_ADVANCED=n
202 Tracking FTP connections is problematic: special helpers are
203 required for tracking them, and doing masquerading and other forms
204 of Network Address Translation on them.
206 This is FTP support on Layer 3 independent connection tracking.
207 Layer 3 independent connection tracking is experimental scheme
208 which generalize ip_conntrack to support other layer 3 protocols.
210 To compile it as a module, choose M here. If unsure, say N.
212 config NF_CONNTRACK_H323
213 tristate "H.323 protocol support"
214 depends on IPV6 || IPV6=n
215 depends on NETFILTER_ADVANCED
217 H.323 is a VoIP signalling protocol from ITU-T. As one of the most
218 important VoIP protocols, it is widely used by voice hardware and
219 software including voice gateways, IP phones, Netmeeting, OpenPhone,
222 With this module you can support H.323 on a connection tracking/NAT
225 This module supports RAS, Fast Start, H.245 Tunnelling, Call
226 Forwarding, RTP/RTCP and T.120 based audio, video, fax, chat,
227 whiteboard, file transfer, etc. For more information, please
228 visit http://nath323.sourceforge.net/.
230 To compile it as a module, choose M here. If unsure, say N.
232 config NF_CONNTRACK_IRC
233 tristate "IRC protocol support"
234 default m if NETFILTER_ADVANCED=n
236 There is a commonly-used extension to IRC called
237 Direct Client-to-Client Protocol (DCC). This enables users to send
238 files to each other, and also chat to each other without the need
239 of a server. DCC Sending is used anywhere you send files over IRC,
240 and DCC Chat is most commonly used by Eggdrop bots. If you are
241 using NAT, this extension will enable you to send files and initiate
242 chats. Note that you do NOT need this extension to get files or
243 have others initiate chats, or everything else in IRC.
245 To compile it as a module, choose M here. If unsure, say N.
247 config NF_CONNTRACK_BROADCAST
250 config NF_CONNTRACK_NETBIOS_NS
251 tristate "NetBIOS name service protocol support"
252 select NF_CONNTRACK_BROADCAST
254 NetBIOS name 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 NetBIOS name service requests and the corresponding
259 responses. It relies on correct IP address configuration, specifically
260 netmask and broadcast address. When properly configured, the output
261 of "ip address show" should look similar to this:
263 $ ip -4 address show eth0
264 4: eth0: <BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 1000
265 inet 172.16.2.252/24 brd 172.16.2.255 scope global eth0
267 To compile it as a module, choose M here. If unsure, say N.
269 config NF_CONNTRACK_SNMP
270 tristate "SNMP service protocol support"
271 depends on NETFILTER_ADVANCED
272 select NF_CONNTRACK_BROADCAST
274 SNMP service requests are sent as broadcast messages from an
275 unprivileged port and responded to with unicast messages to the
276 same port. This make them hard to firewall properly because connection
277 tracking doesn't deal with broadcasts. This helper tracks locally
278 originating SNMP service requests and the corresponding
279 responses. It relies on correct IP address configuration, specifically
280 netmask and broadcast address.
282 To compile it as a module, choose M here. If unsure, say N.
284 config NF_CONNTRACK_PPTP
285 tristate "PPtP protocol support"
286 depends on NETFILTER_ADVANCED
287 select NF_CT_PROTO_GRE
289 This module adds support for PPTP (Point to Point Tunnelling
290 Protocol, RFC2637) connection tracking and NAT.
292 If you are running PPTP sessions over a stateful firewall or NAT
293 box, you may want to enable this feature.
295 Please note that not all PPTP modes of operation are supported yet.
296 Specifically these limitations exist:
297 - Blindly assumes that control connections are always established
298 in PNS->PAC direction. This is a violation of RFC2637.
299 - Only supports a single call within each session
301 To compile it as a module, choose M here. If unsure, say N.
303 config NF_CONNTRACK_SANE
304 tristate "SANE protocol support"
305 depends on NETFILTER_ADVANCED
307 SANE is a protocol for remote access to scanners as implemented
308 by the 'saned' daemon. Like FTP, it uses separate control and
311 With this module you can support SANE on a connection tracking
314 To compile it as a module, choose M here. If unsure, say N.
316 config NF_CONNTRACK_SIP
317 tristate "SIP protocol support"
318 default m if NETFILTER_ADVANCED=n
320 SIP is an application-layer control protocol that can establish,
321 modify, and terminate multimedia sessions (conferences) such as
322 Internet telephony calls. With the ip_conntrack_sip and
323 the nf_nat_sip modules you can support the protocol on a connection
324 tracking/NATing firewall.
326 To compile it as a module, choose M here. If unsure, say N.
328 config NF_CONNTRACK_TFTP
329 tristate "TFTP protocol support"
330 depends on NETFILTER_ADVANCED
332 TFTP connection tracking helper, this is required depending
333 on how restrictive your ruleset is.
334 If you are using a tftp client behind -j SNAT or -j MASQUERADING
337 To compile it as a module, choose M here. If unsure, say N.
340 tristate 'Connection tracking netlink interface'
341 select NETFILTER_NETLINK
342 default m if NETFILTER_ADVANCED=n
344 This option enables support for a netlink-based userspace interface
346 config NF_CT_NETLINK_TIMEOUT
347 tristate 'Connection tracking timeout tuning via Netlink'
348 select NETFILTER_NETLINK
349 depends on NETFILTER_ADVANCED
351 This option enables support for connection tracking timeout
352 fine-grain tuning. This allows you to attach specific timeout
353 policies to flows, instead of using the global timeout policy.
357 config NF_CT_NETLINK_HELPER
358 tristate 'Connection tracking helpers in user-space via Netlink'
359 select NETFILTER_NETLINK
360 depends on NF_CT_NETLINK
361 depends on NETFILTER_NETLINK_QUEUE
362 depends on NETFILTER_NETLINK_GLUE_CT
363 depends on NETFILTER_ADVANCED
365 This option enables the user-space connection tracking helpers
370 config NETFILTER_NETLINK_GLUE_CT
371 bool "NFQUEUE and NFLOG integration with Connection Tracking"
373 depends on (NETFILTER_NETLINK_QUEUE || NETFILTER_NETLINK_LOG) && NF_CT_NETLINK
375 If this option is enabled, NFQUEUE and NFLOG can include
376 Connection Tracking information together with the packet is
377 the enqueued via NFNETLINK.
387 config NF_NAT_PROTO_DCCP
389 depends on NF_NAT && NF_CT_PROTO_DCCP
390 default NF_NAT && NF_CT_PROTO_DCCP
392 config NF_NAT_PROTO_UDPLITE
394 depends on NF_NAT && NF_CT_PROTO_UDPLITE
395 default NF_NAT && NF_CT_PROTO_UDPLITE
397 config NF_NAT_PROTO_SCTP
399 default NF_NAT && NF_CT_PROTO_SCTP
400 depends on NF_NAT && NF_CT_PROTO_SCTP
404 depends on NF_CONNTRACK && NF_NAT
405 default NF_NAT && NF_CONNTRACK_AMANDA
409 depends on NF_CONNTRACK && NF_NAT
410 default NF_NAT && NF_CONNTRACK_FTP
414 depends on NF_CONNTRACK && NF_NAT
415 default NF_NAT && NF_CONNTRACK_IRC
419 depends on NF_CONNTRACK && NF_NAT
420 default NF_NAT && NF_CONNTRACK_SIP
424 depends on NF_CONNTRACK && NF_NAT
425 default NF_NAT && NF_CONNTRACK_TFTP
427 config NF_NAT_REDIRECT
428 tristate "IPv4/IPv6 redirect support"
431 This is the kernel functionality to redirect packets to local
434 config NETFILTER_SYNPROXY
440 select NETFILTER_NETLINK
441 tristate "Netfilter nf_tables support"
443 nftables is the new packet classification framework that intends to
444 replace the existing {ip,ip6,arp,eb}_tables infrastructure. It
445 provides a pseudo-state machine with an extensible instruction-set
446 (also known as expressions) that the userspace 'nft' utility
447 (http://www.netfilter.org/projects/nftables) uses to build the
448 rule-set. It also comes with the generic set infrastructure that
449 allows you to construct mappings between matchings and actions
450 for performance lookups.
452 To compile it as a module, choose M here.
456 config NF_TABLES_INET
458 select NF_TABLES_IPV4
459 select NF_TABLES_IPV6
460 tristate "Netfilter nf_tables mixed IPv4/IPv6 tables support"
462 This option enables support for a mixed IPv4/IPv6 "inet" table.
464 config NF_TABLES_NETDEV
465 tristate "Netfilter nf_tables netdev tables support"
467 This option enables support for the "netdev" table.
470 tristate "Netfilter nf_tables IPv6 exthdr module"
472 This option adds the "exthdr" expression that you can use to match
473 IPv6 extension headers.
476 tristate "Netfilter nf_tables meta module"
478 This option adds the "meta" expression that you can use to match and
479 to set packet metainformation such as the packet mark.
482 tristate "Netfilter nf_tables routing module"
484 This option adds the "rt" expression that you can use to match
485 packet routing information such as the packet nexthop.
488 tristate "Netfilter nf_tables number generator module"
490 This option adds the number generator expression used to perform
491 incremental counting and random numbers bound to a upper limit.
494 depends on NF_CONNTRACK
495 tristate "Netfilter nf_tables conntrack module"
497 This option adds the "ct" expression that you can use to match
498 connection tracking information such as the flow state.
500 config NFT_SET_RBTREE
501 tristate "Netfilter nf_tables rbtree set module"
503 This option adds the "rbtree" set type (Red Black tree) that is used
504 to build interval-based sets.
507 tristate "Netfilter nf_tables hash set module"
509 This option adds the "hash" set type that is used to build one-way
510 mappings between matchings and actions.
513 tristate "Netfilter nf_tables counter module"
515 This option adds the "counter" expression that you can use to
516 include packet and byte counters in a rule.
519 tristate "Netfilter nf_tables log module"
521 This option adds the "log" expression that you can use to log
522 packets matching some criteria.
525 tristate "Netfilter nf_tables limit module"
527 This option adds the "limit" expression that you can use to
528 ratelimit rule matchings.
531 depends on NF_CONNTRACK
533 tristate "Netfilter nf_tables masquerade support"
535 This option adds the "masquerade" expression that you can use
536 to perform NAT in the masquerade flavour.
539 depends on NF_CONNTRACK
541 tristate "Netfilter nf_tables redirect support"
543 This options adds the "redirect" expression that you can use
544 to perform NAT in the redirect flavour.
547 depends on NF_CONNTRACK
549 tristate "Netfilter nf_tables nat module"
551 This option adds the "nat" expression that you can use to perform
552 typical Network Address Translation (NAT) packet transformations.
555 tristate "Netfilter nf_tables stateful object reference module"
557 This option adds the "objref" expression that allows you to refer to
558 stateful objects, such as counters and quotas.
561 depends on NETFILTER_NETLINK_QUEUE
562 tristate "Netfilter nf_tables queue module"
564 This is required if you intend to use the userspace queueing
565 infrastructure (also known as NFQUEUE) from nftables.
568 tristate "Netfilter nf_tables quota module"
570 This option adds the "quota" expression that you can use to match
571 enforce bytes quotas.
574 default m if NETFILTER_ADVANCED=n
575 tristate "Netfilter nf_tables reject support"
577 This option adds the "reject" expression that you can use to
578 explicitly deny and notify via TCP reset/ICMP informational errors
581 config NFT_REJECT_INET
582 depends on NF_TABLES_INET
587 depends on NETFILTER_XTABLES
588 tristate "Netfilter x_tables over nf_tables module"
590 This is required if you intend to use any of existing
591 x_tables match/target extensions over the nf_tables
595 tristate "Netfilter nf_tables hash module"
597 This option adds the "hash" expression that you can use to perform
598 a hash operation on registers.
604 depends on NF_TABLES_INET
605 depends on NFT_FIB_IPV4
606 depends on NFT_FIB_IPV6
607 tristate "Netfilter nf_tables fib inet support"
609 This option allows using the FIB expression from the inet table.
610 The lookup will be delegated to the IPv4 or IPv6 FIB depending
611 on the protocol of the packet.
616 tristate "Netfilter packet duplication support"
618 This option enables the generic packet duplication infrastructure
621 config NFT_DUP_NETDEV
622 tristate "Netfilter nf_tables netdev packet duplication support"
625 This option enables packet duplication for the "netdev" family.
627 config NFT_FWD_NETDEV
628 tristate "Netfilter nf_tables netdev packet forwarding support"
631 This option enables packet forwarding for the "netdev" family.
633 endif # NF_TABLES_NETDEV
637 config NETFILTER_XTABLES
638 tristate "Netfilter Xtables support (required for ip_tables)"
639 default m if NETFILTER_ADVANCED=n
641 This is required if you intend to use any of ip_tables,
642 ip6_tables or arp_tables.
646 comment "Xtables combined modules"
648 config NETFILTER_XT_MARK
649 tristate 'nfmark target and match support'
650 default m if NETFILTER_ADVANCED=n
652 This option adds the "MARK" target and "mark" match.
654 Netfilter mark matching allows you to match packets based on the
655 "nfmark" value in the packet.
656 The target allows you to create rules in the "mangle" table which alter
657 the netfilter mark (nfmark) field associated with the packet.
659 Prior to routing, the nfmark can influence the routing method and can
660 also be used by other subsystems to change their behavior.
662 config NETFILTER_XT_CONNMARK
663 tristate 'ctmark target and match support'
664 depends on NF_CONNTRACK
665 depends on NETFILTER_ADVANCED
666 select NF_CONNTRACK_MARK
668 This option adds the "CONNMARK" target and "connmark" match.
670 Netfilter allows you to store a mark value per connection (a.k.a.
671 ctmark), similarly to the packet mark (nfmark). Using this
672 target and match, you can set and match on this mark.
674 config NETFILTER_XT_SET
675 tristate 'set target and match support'
677 depends on NETFILTER_ADVANCED
679 This option adds the "SET" target and "set" match.
681 Using this target and match, you can add/delete and match
682 elements in the sets created by ipset(8).
684 To compile it as a module, choose M here. If unsure, say N.
686 # alphabetically ordered list of targets
688 comment "Xtables targets"
690 config NETFILTER_XT_TARGET_AUDIT
691 tristate "AUDIT target support"
693 depends on NETFILTER_ADVANCED
695 This option adds a 'AUDIT' target, which can be used to create
696 audit records for packets dropped/accepted.
698 To compileit as a module, choose M here. If unsure, say N.
700 config NETFILTER_XT_TARGET_CHECKSUM
701 tristate "CHECKSUM target support"
702 depends on IP_NF_MANGLE || IP6_NF_MANGLE
703 depends on NETFILTER_ADVANCED
705 This option adds a `CHECKSUM' target, which can be used in the iptables mangle
708 You can use this target to compute and fill in the checksum in
709 a packet that lacks a checksum. This is particularly useful,
710 if you need to work around old applications such as dhcp clients,
711 that do not work well with checksum offloads, but don't want to disable
712 checksum offload in your device.
714 To compile it as a module, choose M here. If unsure, say N.
716 config NETFILTER_XT_TARGET_CLASSIFY
717 tristate '"CLASSIFY" target support'
718 depends on NETFILTER_ADVANCED
720 This option adds a `CLASSIFY' target, which enables the user to set
721 the priority of a packet. Some qdiscs can use this value for
722 classification, among these are:
724 atm, cbq, dsmark, pfifo_fast, htb, prio
726 To compile it as a module, choose M here. If unsure, say N.
728 config NETFILTER_XT_TARGET_CONNMARK
729 tristate '"CONNMARK" target support'
730 depends on NF_CONNTRACK
731 depends on NETFILTER_ADVANCED
732 select NETFILTER_XT_CONNMARK
734 This is a backwards-compat option for the user's convenience
735 (e.g. when running oldconfig). It selects
736 CONFIG_NETFILTER_XT_CONNMARK (combined connmark/CONNMARK module).
738 config NETFILTER_XT_TARGET_CONNSECMARK
739 tristate '"CONNSECMARK" target support'
740 depends on NF_CONNTRACK && NF_CONNTRACK_SECMARK
741 default m if NETFILTER_ADVANCED=n
743 The CONNSECMARK target copies security markings from packets
744 to connections, and restores security markings from connections
745 to packets (if the packets are not already marked). This would
746 normally be used in conjunction with the SECMARK target.
748 To compile it as a module, choose M here. If unsure, say N.
750 config NETFILTER_XT_TARGET_CT
751 tristate '"CT" target support'
752 depends on NF_CONNTRACK
753 depends on IP_NF_RAW || IP6_NF_RAW
754 depends on NETFILTER_ADVANCED
756 This options adds a `CT' target, which allows to specify initial
757 connection tracking parameters like events to be delivered and
758 the helper to be used.
760 To compile it as a module, choose M here. If unsure, say N.
762 config NETFILTER_XT_TARGET_DSCP
763 tristate '"DSCP" and "TOS" target support'
764 depends on IP_NF_MANGLE || IP6_NF_MANGLE
765 depends on NETFILTER_ADVANCED
767 This option adds a `DSCP' target, which allows you to manipulate
768 the IPv4/IPv6 header DSCP field (differentiated services codepoint).
770 The DSCP field can have any value between 0x0 and 0x3f inclusive.
772 It also adds the "TOS" target, which allows you to create rules in
773 the "mangle" table which alter the Type Of Service field of an IPv4
774 or the Priority field of an IPv6 packet, prior to routing.
776 To compile it as a module, choose M here. If unsure, say N.
778 config NETFILTER_XT_TARGET_HL
779 tristate '"HL" hoplimit target support'
780 depends on IP_NF_MANGLE || IP6_NF_MANGLE
781 depends on NETFILTER_ADVANCED
783 This option adds the "HL" (for IPv6) and "TTL" (for IPv4)
784 targets, which enable the user to change the
785 hoplimit/time-to-live value of the IP header.
787 While it is safe to decrement the hoplimit/TTL value, the
788 modules also allow to increment and set the hoplimit value of
789 the header to arbitrary values. This is EXTREMELY DANGEROUS
790 since you can easily create immortal packets that loop
791 forever on the network.
793 config NETFILTER_XT_TARGET_HMARK
794 tristate '"HMARK" target support'
795 depends on IP6_NF_IPTABLES || IP6_NF_IPTABLES=n
796 depends on NETFILTER_ADVANCED
798 This option adds the "HMARK" target.
800 The target allows you to create rules in the "raw" and "mangle" tables
801 which set the skbuff mark by means of hash calculation within a given
802 range. The nfmark can influence the routing method and can also be used
803 by other subsystems to change their behaviour.
805 To compile it as a module, choose M here. If unsure, say N.
807 config NETFILTER_XT_TARGET_IDLETIMER
808 tristate "IDLETIMER target support"
809 depends on NETFILTER_ADVANCED
812 This option adds the `IDLETIMER' target. Each matching packet
813 resets the timer associated with label specified when the rule is
814 added. When the timer expires, it triggers a sysfs notification.
815 The remaining time for expiration can be read via sysfs.
817 To compile it as a module, choose M here. If unsure, say N.
819 config NETFILTER_XT_TARGET_LED
820 tristate '"LED" target support'
821 depends on LEDS_CLASS && LEDS_TRIGGERS
822 depends on NETFILTER_ADVANCED
824 This option adds a `LED' target, which allows you to blink LEDs in
825 response to particular packets passing through your machine.
827 This can be used to turn a spare LED into a network activity LED,
828 which only flashes in response to FTP transfers, for example. Or
829 you could have an LED which lights up for a minute or two every time
830 somebody connects to your machine via SSH.
832 You will need support for the "led" class to make this work.
834 To create an LED trigger for incoming SSH traffic:
835 iptables -A INPUT -p tcp --dport 22 -j LED --led-trigger-id ssh --led-delay 1000
837 Then attach the new trigger to an LED on your system:
838 echo netfilter-ssh > /sys/class/leds/<ledname>/trigger
840 For more information on the LEDs available on your system, see
841 Documentation/leds/leds-class.txt
843 config NETFILTER_XT_TARGET_LOG
844 tristate "LOG target support"
847 select NF_LOG_IPV6 if IPV6
848 default m if NETFILTER_ADVANCED=n
850 This option adds a `LOG' target, which allows you to create rules in
851 any iptables table which records the packet header to the syslog.
853 To compile it as a module, choose M here. If unsure, say N.
855 config NETFILTER_XT_TARGET_MARK
856 tristate '"MARK" target support'
857 depends on NETFILTER_ADVANCED
858 select NETFILTER_XT_MARK
860 This is a backwards-compat option for the user's convenience
861 (e.g. when running oldconfig). It selects
862 CONFIG_NETFILTER_XT_MARK (combined mark/MARK module).
864 config NETFILTER_XT_NAT
865 tristate '"SNAT and DNAT" targets support'
868 This option enables the SNAT and DNAT targets.
870 To compile it as a module, choose M here. If unsure, say N.
872 config NETFILTER_XT_TARGET_NETMAP
873 tristate '"NETMAP" target support'
876 NETMAP is an implementation of static 1:1 NAT mapping of network
877 addresses. It maps the network address part, while keeping the host
880 To compile it as a module, choose M here. If unsure, say N.
882 config NETFILTER_XT_TARGET_NFLOG
883 tristate '"NFLOG" target support'
884 default m if NETFILTER_ADVANCED=n
885 select NETFILTER_NETLINK_LOG
887 This option enables the NFLOG target, which allows to LOG
888 messages through nfnetlink_log.
890 To compile it as a module, choose M here. If unsure, say N.
892 config NETFILTER_XT_TARGET_NFQUEUE
893 tristate '"NFQUEUE" target Support'
894 depends on NETFILTER_ADVANCED
895 select NETFILTER_NETLINK_QUEUE
897 This target replaced the old obsolete QUEUE target.
899 As opposed to QUEUE, it supports 65535 different queues,
902 To compile it as a module, choose M here. If unsure, say N.
904 config NETFILTER_XT_TARGET_NOTRACK
905 tristate '"NOTRACK" target support (DEPRECATED)'
906 depends on NF_CONNTRACK
907 depends on IP_NF_RAW || IP6_NF_RAW
908 depends on NETFILTER_ADVANCED
909 select NETFILTER_XT_TARGET_CT
911 config NETFILTER_XT_TARGET_RATEEST
912 tristate '"RATEEST" target support'
913 depends on NETFILTER_ADVANCED
915 This option adds a `RATEEST' target, which allows to measure
916 rates similar to TC estimators. The `rateest' match can be
917 used to match on the measured rates.
919 To compile it as a module, choose M here. If unsure, say N.
921 config NETFILTER_XT_TARGET_REDIRECT
922 tristate "REDIRECT target support"
924 select NF_NAT_REDIRECT
926 REDIRECT is a special case of NAT: all incoming connections are
927 mapped onto the incoming interface's address, causing the packets to
928 come to the local machine instead of passing through. This is
929 useful for transparent proxies.
931 To compile it as a module, choose M here. If unsure, say N.
933 config NETFILTER_XT_TARGET_TEE
934 tristate '"TEE" - packet cloning to alternate destination'
935 depends on NETFILTER_ADVANCED
936 depends on IPV6 || IPV6=n
937 depends on !NF_CONNTRACK || NF_CONNTRACK
939 select NF_DUP_IPV6 if IPV6
941 This option adds a "TEE" target with which a packet can be cloned and
942 this clone be rerouted to another nexthop.
944 config NETFILTER_XT_TARGET_TPROXY
945 tristate '"TPROXY" target transparent proxying support'
946 depends on NETFILTER_XTABLES
947 depends on NETFILTER_ADVANCED
948 depends on IPV6 || IPV6=n
949 depends on IP6_NF_IPTABLES || IP6_NF_IPTABLES=n
950 depends on IP_NF_MANGLE
951 select NF_DEFRAG_IPV4
952 select NF_DEFRAG_IPV6 if IP6_NF_IPTABLES != n
954 This option adds a `TPROXY' target, which is somewhat similar to
955 REDIRECT. It can only be used in the mangle table and is useful
956 to redirect traffic to a transparent proxy. It does _not_ depend
957 on Netfilter connection tracking and NAT, unlike REDIRECT.
958 For it to work you will have to configure certain iptables rules
959 and use policy routing. For more information on how to set it up
960 see Documentation/networking/tproxy.txt.
962 To compile it as a module, choose M here. If unsure, say N.
964 config NETFILTER_XT_TARGET_TRACE
965 tristate '"TRACE" target support'
966 depends on IP_NF_RAW || IP6_NF_RAW
967 depends on NETFILTER_ADVANCED
969 The TRACE target allows you to mark packets so that the kernel
970 will log every rule which match the packets as those traverse
971 the tables, chains, rules.
973 If you want to compile it as a module, say M here and read
974 <file:Documentation/kbuild/modules.txt>. If unsure, say `N'.
976 config NETFILTER_XT_TARGET_SECMARK
977 tristate '"SECMARK" target support'
978 depends on NETWORK_SECMARK
979 default m if NETFILTER_ADVANCED=n
981 The SECMARK target allows security marking of network
982 packets, for use with security subsystems.
984 To compile it as a module, choose M here. If unsure, say N.
986 config NETFILTER_XT_TARGET_TCPMSS
987 tristate '"TCPMSS" target support'
988 depends on IPV6 || IPV6=n
989 default m if NETFILTER_ADVANCED=n
991 This option adds a `TCPMSS' target, which allows you to alter the
992 MSS value of TCP SYN packets, to control the maximum size for that
993 connection (usually limiting it to your outgoing interface's MTU
996 This is used to overcome criminally braindead ISPs or servers which
997 block ICMP Fragmentation Needed packets. The symptoms of this
998 problem are that everything works fine from your Linux
999 firewall/router, but machines behind it can never exchange large
1001 1) Web browsers connect, then hang with no data received.
1002 2) Small mail works fine, but large emails hang.
1003 3) ssh works fine, but scp hangs after initial handshaking.
1005 Workaround: activate this option and add a rule to your firewall
1008 iptables -A FORWARD -p tcp --tcp-flags SYN,RST SYN \
1009 -j TCPMSS --clamp-mss-to-pmtu
1011 To compile it as a module, choose M here. If unsure, say N.
1013 config NETFILTER_XT_TARGET_TCPOPTSTRIP
1014 tristate '"TCPOPTSTRIP" target support'
1015 depends on IP_NF_MANGLE || IP6_NF_MANGLE
1016 depends on NETFILTER_ADVANCED
1018 This option adds a "TCPOPTSTRIP" target, which allows you to strip
1019 TCP options from TCP packets.
1021 # alphabetically ordered list of matches
1023 comment "Xtables matches"
1025 config NETFILTER_XT_MATCH_ADDRTYPE
1026 tristate '"addrtype" address type match support'
1027 default m if NETFILTER_ADVANCED=n
1029 This option allows you to match what routing thinks of an address,
1030 eg. UNICAST, LOCAL, BROADCAST, ...
1032 If you want to compile it as a module, say M here and read
1033 <file:Documentation/kbuild/modules.txt>. If unsure, say `N'.
1035 config NETFILTER_XT_MATCH_BPF
1036 tristate '"bpf" match support'
1037 depends on NETFILTER_ADVANCED
1039 BPF matching applies a linux socket filter to each packet and
1040 accepts those for which the filter returns non-zero.
1042 To compile it as a module, choose M here. If unsure, say N.
1044 config NETFILTER_XT_MATCH_CGROUP
1045 tristate '"control group" match support'
1046 depends on NETFILTER_ADVANCED
1048 select CGROUP_NET_CLASSID
1050 Socket/process control group matching allows you to match locally
1051 generated packets based on which net_cls control group processes
1054 config NETFILTER_XT_MATCH_CLUSTER
1055 tristate '"cluster" match support'
1056 depends on NF_CONNTRACK
1057 depends on NETFILTER_ADVANCED
1059 This option allows you to build work-load-sharing clusters of
1060 network servers/stateful firewalls without having a dedicated
1061 load-balancing router/server/switch. Basically, this match returns
1062 true when the packet must be handled by this cluster node. Thus,
1063 all nodes see all packets and this match decides which node handles
1064 what packets. The work-load sharing algorithm is based on source
1067 If you say Y or M here, try `iptables -m cluster --help` for
1070 config NETFILTER_XT_MATCH_COMMENT
1071 tristate '"comment" match support'
1072 depends on NETFILTER_ADVANCED
1074 This option adds a `comment' dummy-match, which allows you to put
1075 comments in your iptables ruleset.
1077 If you want to compile it as a module, say M here and read
1078 <file:Documentation/kbuild/modules.txt>. If unsure, say `N'.
1080 config NETFILTER_XT_MATCH_CONNBYTES
1081 tristate '"connbytes" per-connection counter match support'
1082 depends on NF_CONNTRACK
1083 depends on NETFILTER_ADVANCED
1085 This option adds a `connbytes' match, which allows you to match the
1086 number of bytes and/or packets for each direction within a connection.
1088 If you want to compile it as a module, say M here and read
1089 <file:Documentation/kbuild/modules.txt>. If unsure, say `N'.
1091 config NETFILTER_XT_MATCH_CONNLABEL
1092 tristate '"connlabel" match support'
1093 select NF_CONNTRACK_LABELS
1094 depends on NF_CONNTRACK
1095 depends on NETFILTER_ADVANCED
1097 This match allows you to test and assign userspace-defined labels names
1098 to a connection. The kernel only stores bit values - mapping
1099 names to bits is done by userspace.
1101 Unlike connmark, more than 32 flag bits may be assigned to a
1102 connection simultaneously.
1104 config NETFILTER_XT_MATCH_CONNLIMIT
1105 tristate '"connlimit" match support'
1106 depends on NF_CONNTRACK
1107 depends on NETFILTER_ADVANCED
1109 This match allows you to match against the number of parallel
1110 connections to a server per client IP address (or address block).
1112 config NETFILTER_XT_MATCH_CONNMARK
1113 tristate '"connmark" connection mark match support'
1114 depends on NF_CONNTRACK
1115 depends on NETFILTER_ADVANCED
1116 select NETFILTER_XT_CONNMARK
1118 This is a backwards-compat option for the user's convenience
1119 (e.g. when running oldconfig). It selects
1120 CONFIG_NETFILTER_XT_CONNMARK (combined connmark/CONNMARK module).
1122 config NETFILTER_XT_MATCH_CONNTRACK
1123 tristate '"conntrack" connection tracking match support'
1124 depends on NF_CONNTRACK
1125 default m if NETFILTER_ADVANCED=n
1127 This is a general conntrack match module, a superset of the state match.
1129 It allows matching on additional conntrack information, which is
1130 useful in complex configurations, such as NAT gateways with multiple
1131 internet links or tunnels.
1133 To compile it as a module, choose M here. If unsure, say N.
1135 config NETFILTER_XT_MATCH_CPU
1136 tristate '"cpu" match support'
1137 depends on NETFILTER_ADVANCED
1139 CPU matching allows you to match packets based on the CPU
1140 currently handling the packet.
1142 To compile it as a module, choose M here. If unsure, say N.
1144 config NETFILTER_XT_MATCH_DCCP
1145 tristate '"dccp" protocol match support'
1146 depends on NETFILTER_ADVANCED
1149 With this option enabled, you will be able to use the iptables
1150 `dccp' match in order to match on DCCP source/destination ports
1153 If you want to compile it as a module, say M here and read
1154 <file:Documentation/kbuild/modules.txt>. If unsure, say `N'.
1156 config NETFILTER_XT_MATCH_DEVGROUP
1157 tristate '"devgroup" match support'
1158 depends on NETFILTER_ADVANCED
1160 This options adds a `devgroup' match, which allows to match on the
1161 device group a network device is assigned to.
1163 To compile it as a module, choose M here. If unsure, say N.
1165 config NETFILTER_XT_MATCH_DSCP
1166 tristate '"dscp" and "tos" match support'
1167 depends on NETFILTER_ADVANCED
1169 This option adds a `DSCP' match, which allows you to match against
1170 the IPv4/IPv6 header DSCP field (differentiated services codepoint).
1172 The DSCP field can have any value between 0x0 and 0x3f inclusive.
1174 It will also add a "tos" match, which allows you to match packets
1175 based on the Type Of Service fields of the IPv4 packet (which share
1176 the same bits as DSCP).
1178 To compile it as a module, choose M here. If unsure, say N.
1180 config NETFILTER_XT_MATCH_ECN
1181 tristate '"ecn" match support'
1182 depends on NETFILTER_ADVANCED
1184 This option adds an "ECN" match, which allows you to match against
1185 the IPv4 and TCP header ECN fields.
1187 To compile it as a module, choose M here. If unsure, say N.
1189 config NETFILTER_XT_MATCH_ESP
1190 tristate '"esp" match support'
1191 depends on NETFILTER_ADVANCED
1193 This match extension allows you to match a range of SPIs
1194 inside ESP header of IPSec packets.
1196 To compile it as a module, choose M here. If unsure, say N.
1198 config NETFILTER_XT_MATCH_HASHLIMIT
1199 tristate '"hashlimit" match support'
1200 depends on IP6_NF_IPTABLES || IP6_NF_IPTABLES=n
1201 depends on NETFILTER_ADVANCED
1203 This option adds a `hashlimit' match.
1205 As opposed to `limit', this match dynamically creates a hash table
1206 of limit buckets, based on your selection of source/destination
1207 addresses and/or ports.
1209 It enables you to express policies like `10kpps for any given
1210 destination address' or `500pps from any given source address'
1213 config NETFILTER_XT_MATCH_HELPER
1214 tristate '"helper" match support'
1215 depends on NF_CONNTRACK
1216 depends on NETFILTER_ADVANCED
1218 Helper matching allows you to match packets in dynamic connections
1219 tracked by a conntrack-helper, ie. ip_conntrack_ftp
1221 To compile it as a module, choose M here. If unsure, say Y.
1223 config NETFILTER_XT_MATCH_HL
1224 tristate '"hl" hoplimit/TTL match support'
1225 depends on NETFILTER_ADVANCED
1227 HL matching allows you to match packets based on the hoplimit
1228 in the IPv6 header, or the time-to-live field in the IPv4
1229 header of the packet.
1231 config NETFILTER_XT_MATCH_IPCOMP
1232 tristate '"ipcomp" match support'
1233 depends on NETFILTER_ADVANCED
1235 This match extension allows you to match a range of CPIs(16 bits)
1236 inside IPComp header of IPSec packets.
1238 To compile it as a module, choose M here. If unsure, say N.
1240 config NETFILTER_XT_MATCH_IPRANGE
1241 tristate '"iprange" address range match support'
1242 depends on NETFILTER_ADVANCED
1244 This option adds a "iprange" match, which allows you to match based on
1245 an IP address range. (Normal iptables only matches on single addresses
1246 with an optional mask.)
1250 config NETFILTER_XT_MATCH_IPVS
1251 tristate '"ipvs" match support'
1253 depends on NETFILTER_ADVANCED
1254 depends on NF_CONNTRACK
1256 This option allows you to match against IPVS properties of a packet.
1260 config NETFILTER_XT_MATCH_L2TP
1261 tristate '"l2tp" match support'
1262 depends on NETFILTER_ADVANCED
1265 This option adds an "L2TP" match, which allows you to match against
1266 L2TP protocol header fields.
1268 To compile it as a module, choose M here. If unsure, say N.
1270 config NETFILTER_XT_MATCH_LENGTH
1271 tristate '"length" match support'
1272 depends on NETFILTER_ADVANCED
1274 This option allows you to match the length of a packet against a
1275 specific value or range of values.
1277 To compile it as a module, choose M here. If unsure, say N.
1279 config NETFILTER_XT_MATCH_LIMIT
1280 tristate '"limit" match support'
1281 depends on NETFILTER_ADVANCED
1283 limit matching allows you to control the rate at which a rule can be
1284 matched: mainly useful in combination with the LOG target ("LOG
1285 target support", below) and to avoid some Denial of Service attacks.
1287 To compile it as a module, choose M here. If unsure, say N.
1289 config NETFILTER_XT_MATCH_MAC
1290 tristate '"mac" address match support'
1291 depends on NETFILTER_ADVANCED
1293 MAC matching allows you to match packets based on the source
1294 Ethernet address of the packet.
1296 To compile it as a module, choose M here. If unsure, say N.
1298 config NETFILTER_XT_MATCH_MARK
1299 tristate '"mark" match support'
1300 depends on NETFILTER_ADVANCED
1301 select NETFILTER_XT_MARK
1303 This is a backwards-compat option for the user's convenience
1304 (e.g. when running oldconfig). It selects
1305 CONFIG_NETFILTER_XT_MARK (combined mark/MARK module).
1307 config NETFILTER_XT_MATCH_MULTIPORT
1308 tristate '"multiport" Multiple port match support'
1309 depends on NETFILTER_ADVANCED
1311 Multiport matching allows you to match TCP or UDP packets based on
1312 a series of source or destination ports: normally a rule can only
1313 match a single range of ports.
1315 To compile it as a module, choose M here. If unsure, say N.
1317 config NETFILTER_XT_MATCH_NFACCT
1318 tristate '"nfacct" match support'
1319 depends on NETFILTER_ADVANCED
1320 select NETFILTER_NETLINK_ACCT
1322 This option allows you to use the extended accounting through
1325 To compile it as a module, choose M here. If unsure, say N.
1327 config NETFILTER_XT_MATCH_OSF
1328 tristate '"osf" Passive OS fingerprint match'
1329 depends on NETFILTER_ADVANCED && NETFILTER_NETLINK
1331 This option selects the Passive OS Fingerprinting match module
1332 that allows to passively match the remote operating system by
1333 analyzing incoming TCP SYN packets.
1335 Rules and loading software can be downloaded from
1336 http://www.ioremap.net/projects/osf
1338 To compile it as a module, choose M here. If unsure, say N.
1340 config NETFILTER_XT_MATCH_OWNER
1341 tristate '"owner" match support'
1342 depends on NETFILTER_ADVANCED
1344 Socket owner matching allows you to match locally-generated packets
1345 based on who created the socket: the user or group. It is also
1346 possible to check whether a socket actually exists.
1348 config NETFILTER_XT_MATCH_POLICY
1349 tristate 'IPsec "policy" match support'
1351 default m if NETFILTER_ADVANCED=n
1353 Policy matching allows you to match packets based on the
1354 IPsec policy that was used during decapsulation/will
1355 be used during encapsulation.
1357 To compile it as a module, choose M here. If unsure, say N.
1359 config NETFILTER_XT_MATCH_PHYSDEV
1360 tristate '"physdev" match support'
1361 depends on BRIDGE && BRIDGE_NETFILTER
1362 depends on NETFILTER_ADVANCED
1364 Physdev packet matching matches against the physical bridge ports
1365 the IP packet arrived on or will leave by.
1367 To compile it as a module, choose M here. If unsure, say N.
1369 config NETFILTER_XT_MATCH_PKTTYPE
1370 tristate '"pkttype" packet type match support'
1371 depends on NETFILTER_ADVANCED
1373 Packet type matching allows you to match a packet by
1374 its "class", eg. BROADCAST, MULTICAST, ...
1377 iptables -A INPUT -m pkttype --pkt-type broadcast -j LOG
1379 To compile it as a module, choose M here. If unsure, say N.
1381 config NETFILTER_XT_MATCH_QUOTA
1382 tristate '"quota" match support'
1383 depends on NETFILTER_ADVANCED
1385 This option adds a `quota' match, which allows to match on a
1388 If you want to compile it as a module, say M here and read
1389 <file:Documentation/kbuild/modules.txt>. If unsure, say `N'.
1391 config NETFILTER_XT_MATCH_RATEEST
1392 tristate '"rateest" match support'
1393 depends on NETFILTER_ADVANCED
1394 select NETFILTER_XT_TARGET_RATEEST
1396 This option adds a `rateest' match, which allows to match on the
1397 rate estimated by the RATEEST target.
1399 To compile it as a module, choose M here. If unsure, say N.
1401 config NETFILTER_XT_MATCH_REALM
1402 tristate '"realm" match support'
1403 depends on NETFILTER_ADVANCED
1404 select IP_ROUTE_CLASSID
1406 This option adds a `realm' match, which allows you to use the realm
1407 key from the routing subsystem inside iptables.
1409 This match pretty much resembles the CONFIG_NET_CLS_ROUTE4 option
1412 If you want to compile it as a module, say M here and read
1413 <file:Documentation/kbuild/modules.txt>. If unsure, say `N'.
1415 config NETFILTER_XT_MATCH_RECENT
1416 tristate '"recent" match support'
1417 depends on NETFILTER_ADVANCED
1419 This match is used for creating one or many lists of recently
1420 used addresses and then matching against that/those list(s).
1422 Short options are available by using 'iptables -m recent -h'
1423 Official Website: <http://snowman.net/projects/ipt_recent/>
1425 config NETFILTER_XT_MATCH_SCTP
1426 tristate '"sctp" protocol match support'
1427 depends on NETFILTER_ADVANCED
1430 With this option enabled, you will be able to use the
1431 `sctp' match in order to match on SCTP source/destination ports
1432 and SCTP chunk types.
1434 If you want to compile it as a module, say M here and read
1435 <file:Documentation/kbuild/modules.txt>. If unsure, say `N'.
1437 config NETFILTER_XT_MATCH_SOCKET
1438 tristate '"socket" match support'
1439 depends on NETFILTER_XTABLES
1440 depends on NETFILTER_ADVANCED
1441 depends on IPV6 || IPV6=n
1442 depends on IP6_NF_IPTABLES || IP6_NF_IPTABLES=n
1443 depends on NF_SOCKET_IPV4
1444 depends on NF_SOCKET_IPV6
1445 select NF_DEFRAG_IPV4
1446 select NF_DEFRAG_IPV6 if IP6_NF_IPTABLES != n
1448 This option adds a `socket' match, which can be used to match
1449 packets for which a TCP or UDP socket lookup finds a valid socket.
1450 It can be used in combination with the MARK target and policy
1451 routing to implement full featured non-locally bound sockets.
1453 To compile it as a module, choose M here. If unsure, say N.
1455 config NETFILTER_XT_MATCH_STATE
1456 tristate '"state" match support'
1457 depends on NF_CONNTRACK
1458 default m if NETFILTER_ADVANCED=n
1460 Connection state matching allows you to match packets based on their
1461 relationship to a tracked connection (ie. previous packets). This
1462 is a powerful tool for packet classification.
1464 To compile it as a module, choose M here. If unsure, say N.
1466 config NETFILTER_XT_MATCH_STATISTIC
1467 tristate '"statistic" match support'
1468 depends on NETFILTER_ADVANCED
1470 This option adds a `statistic' match, which allows you to match
1471 on packets periodically or randomly with a given percentage.
1473 To compile it as a module, choose M here. If unsure, say N.
1475 config NETFILTER_XT_MATCH_STRING
1476 tristate '"string" match support'
1477 depends on NETFILTER_ADVANCED
1479 select TEXTSEARCH_KMP
1480 select TEXTSEARCH_BM
1481 select TEXTSEARCH_FSM
1483 This option adds a `string' match, which allows you to look for
1484 pattern matchings in packets.
1486 To compile it as a module, choose M here. If unsure, say N.
1488 config NETFILTER_XT_MATCH_TCPMSS
1489 tristate '"tcpmss" match support'
1490 depends on NETFILTER_ADVANCED
1492 This option adds a `tcpmss' match, which allows you to examine the
1493 MSS value of TCP SYN packets, which control the maximum packet size
1494 for that connection.
1496 To compile it as a module, choose M here. If unsure, say N.
1498 config NETFILTER_XT_MATCH_TIME
1499 tristate '"time" match support'
1500 depends on NETFILTER_ADVANCED
1502 This option adds a "time" match, which allows you to match based on
1503 the packet arrival time (at the machine which netfilter is running)
1504 on) or departure time/date (for locally generated packets).
1506 If you say Y here, try `iptables -m time --help` for
1509 If you want to compile it as a module, say M here.
1512 config NETFILTER_XT_MATCH_U32
1513 tristate '"u32" match support'
1514 depends on NETFILTER_ADVANCED
1516 u32 allows you to extract quantities of up to 4 bytes from a packet,
1517 AND them with specified masks, shift them by specified amounts and
1518 test whether the results are in any of a set of specified ranges.
1519 The specification of what to extract is general enough to skip over
1520 headers with lengths stored in the packet, as in IP or TCP header
1523 Details and examples are in the kernel module source.
1525 endif # NETFILTER_XTABLES
1529 source "net/netfilter/ipset/Kconfig"
1531 source "net/netfilter/ipvs/Kconfig"