net/ipv4/netfilter/Kconfig

#
# IP netfilter configuration
#

menu "IP: Netfilter Configuration"
	depends on INET && NETFILTER

config NF_CONNTRACK_IPV4
	tristate "IPv4 support for new connection tracking (EXPERIMENTAL)"
	depends on EXPERIMENTAL && NF_CONNTRACK
	---help---
	  Connection tracking keeps a record of what packets have passed
	  through your machine, in order to figure out how they are related
	  into connections.

	  This is IPv4 support on Layer 3 independent connection tracking.
	  Layer 3 independent connection tracking is experimental scheme
	  which generalize ip_conntrack to support other layer 3 protocols.

	  To compile it as a module, choose M here.  If unsure, say N.

# connection tracking, helpers and protocols
config IP_NF_CONNTRACK
	tristate "Connection tracking (required for masq/NAT)"
	---help---
	  Connection tracking keeps a record of what packets have passed
	  through your machine, in order to figure out how they are related
	  into connections.

	  This is required to do Masquerading or other kinds of Network
	  Address Translation (except for Fast NAT).  It can also be used to
	  enhance packet filtering (see `Connection state match support'
	  below).

	  To compile it as a module, choose M here.  If unsure, say N.

config IP_NF_CT_ACCT
	bool "Connection tracking flow accounting"
	depends on IP_NF_CONNTRACK
	help
	  If this option is enabled, the connection tracking code will
	  keep per-flow packet and byte counters.

	  Those counters can be used for flow-based accounting or the
	  `connbytes' match.

	  If unsure, say `N'.

config IP_NF_CONNTRACK_MARK
	bool  'Connection mark tracking support'
	depends on IP_NF_CONNTRACK
	help
	  This option enables support for connection marks, used by the
	  `CONNMARK' target and `connmark' match. Similar to the mark value
	  of packets, but this mark value is kept in the conntrack session
	  instead of the individual packets.
	
config IP_NF_CONNTRACK_EVENTS
	bool "Connection tracking events (EXPERIMENTAL)"
	depends on EXPERIMENTAL && IP_NF_CONNTRACK
	help
	  If this option is enabled, the connection tracking code will
	  provide a notifier chain that can be used by other kernel code
	  to get notified about changes in the connection tracking state.
	  
	  IF unsure, say `N'.

config IP_NF_CONNTRACK_NETLINK
	tristate 'Connection tracking netlink interface (EXPERIMENTAL)'
	depends on EXPERIMENTAL && IP_NF_CONNTRACK && NETFILTER_NETLINK
	depends on IP_NF_CONNTRACK!=y || NETFILTER_NETLINK!=m
	help
	  This option enables support for a netlink-based userspace interface


config IP_NF_CT_PROTO_SCTP
	tristate  'SCTP protocol connection tracking support (EXPERIMENTAL)'
	depends on IP_NF_CONNTRACK && EXPERIMENTAL
	help
	  With this option enabled, the connection tracking code will
	  be able to do state tracking on SCTP connections.

	  If you want to compile it as a module, say M here and read
	  <file:Documentation/modules.txt>.  If unsure, say `N'.

config IP_NF_FTP
	tristate "FTP protocol support"
	depends on IP_NF_CONNTRACK
	help
	  Tracking FTP connections is problematic: special helpers are
	  required for tracking them, and doing masquerading and other forms
	  of Network Address Translation on them.

	  To compile it as a module, choose M here.  If unsure, say Y.

config IP_NF_IRC
	tristate "IRC protocol support"
	depends on IP_NF_CONNTRACK
	---help---
	  There is a commonly-used extension to IRC called
	  Direct Client-to-Client Protocol (DCC).  This enables users to send
	  files to each other, and also chat to each other without the need
	  of a server.  DCC Sending is used anywhere you send files over IRC,
	  and DCC Chat is most commonly used by Eggdrop bots.  If you are
	  using NAT, this extension will enable you to send files and initiate
	  chats.  Note that you do NOT need this extension to get files or
	  have others initiate chats, or everything else in IRC.

	  To compile it as a module, choose M here.  If unsure, say Y.

config IP_NF_NETBIOS_NS
	tristate "NetBIOS name service protocol support (EXPERIMENTAL)"
	depends on IP_NF_CONNTRACK && EXPERIMENTAL
	help
	  NetBIOS name service requests are sent as broadcast messages from an
	  unprivileged port and responded to with unicast messages to the
	  same port. This make them hard to firewall properly because connection
	  tracking doesn't deal with broadcasts. This helper tracks locally
	  originating NetBIOS name service requests and the corresponding
	  responses. It relies on correct IP address configuration, specifically
	  netmask and broadcast address. When properly configured, the output
	  of "ip address show" should look similar to this:

	  $ ip -4 address show eth0
	  4: eth0: <BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 1000
	      inet 172.16.2.252/24 brd 172.16.2.255 scope global eth0
	  
	  To compile it as a module, choose M here.  If unsure, say N.

config IP_NF_TFTP
	tristate "TFTP protocol support"
	depends on IP_NF_CONNTRACK
	help
	  TFTP connection tracking helper, this is required depending
	  on how restrictive your ruleset is.
	  If you are using a tftp client behind -j SNAT or -j MASQUERADING
	  you will need this.

	  To compile it as a module, choose M here.  If unsure, say Y.

config IP_NF_AMANDA
	tristate "Amanda backup protocol support"
	depends on IP_NF_CONNTRACK
	help
	  If you are running the Amanda backup package <http://www.amanda.org/>
	  on this machine or machines that will be MASQUERADED through this
	  machine, then you may want to enable this feature.  This allows the
	  connection tracking and natting code to allow the sub-channels that
	  Amanda requires for communication of the backup data, messages and
	  index.

	  To compile it as a module, choose M here.  If unsure, say Y.

config IP_NF_PPTP
	tristate  'PPTP protocol support'
	depends on IP_NF_CONNTRACK
	help
	  This module adds support for PPTP (Point to Point Tunnelling
	  Protocol, RFC2637) connection tracking and NAT. 
	
	  If you are running PPTP sessions over a stateful firewall or NAT
	  box, you may want to enable this feature.  
	
	  Please note that not all PPTP modes of operation are supported yet.
	  For more info, read top of the file
	  net/ipv4/netfilter/ip_conntrack_pptp.c
	
	  If you want to compile it as a module, say M here and read
	  Documentation/modules.txt.  If unsure, say `N'.

config IP_NF_QUEUE
	tristate "IP Userspace queueing via NETLINK (OBSOLETE)"
	help
	  Netfilter has the ability to queue packets to user space: the
	  netlink device can be used to access them using this driver.

	  This option enables the old IPv4-only "ip_queue" implementation
	  which has been obsoleted by the new "nfnetlink_queue" code (see
	  CONFIG_NETFILTER_NETLINK_QUEUE).

	  To compile it as a module, choose M here.  If unsure, say N.

config IP_NF_IPTABLES
	tristate "IP tables support (required for filtering/masq/NAT)"
	depends on NETFILTER_XTABLES
	help
	  iptables is a general, extensible packet identification framework.
	  The packet filtering and full NAT (masquerading, port forwarding,
	  etc) subsystems now use this: say `Y' or `M' here if you want to use
	  either of those.

	  To compile it as a module, choose M here.  If unsure, say N.

# The matches.
config IP_NF_MATCH_IPRANGE
	tristate "IP range match support"
	depends on IP_NF_IPTABLES
	help
	  This option makes possible to match IP addresses against IP address
	  ranges.

	  To compile it as a module, choose M here.  If unsure, say N.

config IP_NF_MATCH_MULTIPORT
	tristate "Multiple port match support"
	depends on IP_NF_IPTABLES
	help
	  Multiport matching allows you to match TCP or UDP packets based on
	  a series of source or destination ports: normally a rule can only
	  match a single range of ports.

	  To compile it as a module, choose M here.  If unsure, say N.

config IP_NF_MATCH_TOS
	tristate "TOS match support"
	depends on IP_NF_IPTABLES
	help
	  TOS matching allows you to match packets based on the Type Of
	  Service fields of the IP packet.

	  To compile it as a module, choose M here.  If unsure, say N.

config IP_NF_MATCH_RECENT
	tristate "recent match support"
	depends on IP_NF_IPTABLES
	help
	  This match is used for creating one or many lists of recently
	  used addresses and then matching against that/those list(s).

	  Short options are available by using 'iptables -m recent -h'
	  Official Website: <http://snowman.net/projects/ipt_recent/>

	  To compile it as a module, choose M here.  If unsure, say N.

config IP_NF_MATCH_ECN
	tristate "ECN match support"
	depends on IP_NF_IPTABLES
	help
	  This option adds a `ECN' match, which allows you to match against
	  the IPv4 and TCP header ECN fields.

	  To compile it as a module, choose M here.  If unsure, say N.

config IP_NF_MATCH_DSCP
	tristate "DSCP match support"
	depends on IP_NF_IPTABLES
	help
	  This option adds a `DSCP' match, which allows you to match against
	  the IPv4 header DSCP field (DSCP codepoint).

	  The DSCP codepoint can have any value between 0x0 and 0x4f.

	  To compile it as a module, choose M here.  If unsure, say N.

config IP_NF_MATCH_AH_ESP
	tristate "AH/ESP match support"
	depends on IP_NF_IPTABLES
	help
	  These two match extensions (`ah' and `esp') allow you to match a
	  range of SPIs inside AH or ESP headers of IPSec packets.

	  To compile it as a module, choose M here.  If unsure, say N.

config IP_NF_MATCH_TTL
	tristate "TTL match support"
	depends on IP_NF_IPTABLES
	help
	  This adds CONFIG_IP_NF_MATCH_TTL option, which enabled the user
	  to match packets by their TTL value.

	  To compile it as a module, choose M here.  If unsure, say N.

config IP_NF_MATCH_OWNER
	tristate "Owner match support"
	depends on IP_NF_IPTABLES
	help
	  Packet owner matching allows you to match locally-generated packets
	  based on who created them: the user, group, process or session.

	  To compile it as a module, choose M here.  If unsure, say N.

config IP_NF_MATCH_ADDRTYPE
	tristate  'address type match support'
	depends on IP_NF_IPTABLES
	help
	  This option allows you to match what routing thinks of an address,
	  eg. UNICAST, LOCAL, BROADCAST, ...
	
	  If you want to compile it as a module, say M here and read
	  <file:Documentation/modules.txt>.  If unsure, say `N'.

config IP_NF_MATCH_HASHLIMIT
	tristate  'hashlimit match support'
	depends on IP_NF_IPTABLES
	help
	  This option adds a new iptables `hashlimit' match.  

	  As opposed to `limit', this match dynamically crates a hash table
	  of limit buckets, based on your selection of source/destination
	  ip addresses and/or ports.

	  It enables you to express policies like `10kpps for any given
	  destination IP' or `500pps from any given source IP'  with a single
	  IPtables rule.

config IP_NF_MATCH_POLICY
       tristate "IPsec policy match support"
       depends on IP_NF_IPTABLES && XFRM
       help
         Policy matching allows you to match packets based on the
         IPsec policy that was used during decapsulation/will
         be used during encapsulation.

         To compile it as a module, choose M here.  If unsure, say N.

# `filter', generic and specific targets
config IP_NF_FILTER
	tristate "Packet filtering"
	depends on IP_NF_IPTABLES
	help
	  Packet filtering defines a table `filter', which has a series of
	  rules for simple packet filtering at local input, forwarding and
	  local output.  See the man page for iptables(8).

	  To compile it as a module, choose M here.  If unsure, say N.

config IP_NF_TARGET_REJECT
	tristate "REJECT target support"
	depends on IP_NF_FILTER
	help
	  The REJECT target allows a filtering rule to specify that an ICMP
	  error should be issued in response to an incoming packet, rather
	  than silently being dropped.

	  To compile it as a module, choose M here.  If unsure, say N.

config IP_NF_TARGET_LOG
	tristate "LOG target support"
	depends on IP_NF_IPTABLES
	help
	  This option adds a `LOG' target, which allows you to create rules in
	  any iptables table which records the packet header to the syslog.

	  To compile it as a module, choose M here.  If unsure, say N.

config IP_NF_TARGET_ULOG
	tristate "ULOG target support (OBSOLETE)"
	depends on IP_NF_IPTABLES
	---help---

	  This option enables the old IPv4-only "ipt_ULOG" implementation
	  which has been obsoleted by the new "nfnetlink_log" code (see
	  CONFIG_NETFILTER_NETLINK_LOG).

	  This option adds a `ULOG' target, which allows you to create rules in
	  any iptables table. The packet is passed to a userspace logging
	  daemon using netlink multicast sockets; unlike the LOG target
	  which can only be viewed through syslog.

	  The apropriate userspace logging daemon (ulogd) may be obtained from
	  <http://www.gnumonks.org/projects/ulogd/>

	  To compile it as a module, choose M here.  If unsure, say N.

config IP_NF_TARGET_TCPMSS
	tristate "TCPMSS target support"
	depends on IP_NF_IPTABLES
	---help---
	  This option adds a `TCPMSS' target, which allows you to alter the
	  MSS value of TCP SYN packets, to control the maximum size for that
	  connection (usually limiting it to your outgoing interface's MTU
	  minus 40).

	  This is used to overcome criminally braindead ISPs or servers which
	  block ICMP Fragmentation Needed packets.  The symptoms of this
	  problem are that everything works fine from your Linux
	  firewall/router, but machines behind it can never exchange large
	  packets:
	  	1) Web browsers connect, then hang with no data received.
	  	2) Small mail works fine, but large emails hang.
	  	3) ssh works fine, but scp hangs after initial handshaking.

	  Workaround: activate this option and add a rule to your firewall
	  configuration like:

	  iptables -A FORWARD -p tcp --tcp-flags SYN,RST SYN \
	  		 -j TCPMSS --clamp-mss-to-pmtu

	  To compile it as a module, choose M here.  If unsure, say N.

# NAT + specific targets
config IP_NF_NAT
	tristate "Full NAT"
	depends on IP_NF_IPTABLES && IP_NF_CONNTRACK
	help
	  The Full NAT option allows masquerading, port forwarding and other
	  forms of full Network Address Port Translation.  It is controlled by
	  the `nat' table in iptables: see the man page for iptables(8).

	  To compile it as a module, choose M here.  If unsure, say N.

config IP_NF_NAT_NEEDED
	bool
	depends on IP_NF_NAT != n
	default y

config IP_NF_TARGET_MASQUERADE
	tristate "MASQUERADE target support"
	depends on IP_NF_NAT
	help
	  Masquerading is a special case of NAT: all outgoing connections are
	  changed to seem to come from a particular interface's address, and
	  if the interface goes down, those connections are lost.  This is
	  only useful for dialup accounts with dynamic IP address (ie. your IP
	  address will be different on next dialup).

	  To compile it as a module, choose M here.  If unsure, say N.

config IP_NF_TARGET_REDIRECT
	tristate "REDIRECT target support"
	depends on IP_NF_NAT
	help
	  REDIRECT is a special case of NAT: all incoming connections are
	  mapped onto the incoming interface's address, causing the packets to
	  come to the local machine instead of passing through.  This is
	  useful for transparent proxies.

	  To compile it as a module, choose M here.  If unsure, say N.

config IP_NF_TARGET_NETMAP
	tristate "NETMAP target support"
	depends on IP_NF_NAT
	help
	  NETMAP is an implementation of static 1:1 NAT mapping of network
	  addresses. It maps the network address part, while keeping the host
	  address part intact. It is similar to Fast NAT, except that
	  Netfilter's connection tracking doesn't work well with Fast NAT.

	  To compile it as a module, choose M here.  If unsure, say N.

config IP_NF_TARGET_SAME
	tristate "SAME target support"
	depends on IP_NF_NAT
	help
	  This option adds a `SAME' target, which works like the standard SNAT
	  target, but attempts to give clients the same IP for all connections.

	  To compile it as a module, choose M here.  If unsure, say N.

config IP_NF_NAT_SNMP_BASIC
	tristate "Basic SNMP-ALG support (EXPERIMENTAL)"
	depends on EXPERIMENTAL && IP_NF_NAT
	---help---

	  This module implements an Application Layer Gateway (ALG) for
	  SNMP payloads.  In conjunction with NAT, it allows a network
	  management system to access multiple private networks with
	  conflicting addresses.  It works by modifying IP addresses
	  inside SNMP payloads to match IP-layer NAT mapping.

	  This is the "basic" form of SNMP-ALG, as described in RFC 2962

	  To compile it as a module, choose M here.  If unsure, say N.

config IP_NF_NAT_IRC
	tristate
	depends on IP_NF_IPTABLES!=n && IP_NF_CONNTRACK!=n && IP_NF_NAT!=n
	default IP_NF_NAT if IP_NF_IRC=y
	default m if IP_NF_IRC=m

# If they want FTP, set to $CONFIG_IP_NF_NAT (m or y), 
# or $CONFIG_IP_NF_FTP (m or y), whichever is weaker.  Argh.
config IP_NF_NAT_FTP
	tristate
	depends on IP_NF_IPTABLES!=n && IP_NF_CONNTRACK!=n && IP_NF_NAT!=n
	default IP_NF_NAT if IP_NF_FTP=y
	default m if IP_NF_FTP=m

config IP_NF_NAT_TFTP
	tristate
	depends on IP_NF_IPTABLES!=n && IP_NF_CONNTRACK!=n && IP_NF_NAT!=n
	default IP_NF_NAT if IP_NF_TFTP=y
	default m if IP_NF_TFTP=m

config IP_NF_NAT_AMANDA
	tristate
	depends on IP_NF_IPTABLES!=n && IP_NF_CONNTRACK!=n && IP_NF_NAT!=n
	default IP_NF_NAT if IP_NF_AMANDA=y
	default m if IP_NF_AMANDA=m

config IP_NF_NAT_PPTP
	tristate
	depends on IP_NF_NAT!=n && IP_NF_PPTP!=n
	default IP_NF_NAT if IP_NF_PPTP=y
	default m if IP_NF_PPTP=m

# mangle + specific targets
config IP_NF_MANGLE
	tristate "Packet mangling"
	depends on IP_NF_IPTABLES
	help
	  This option adds a `mangle' table to iptables: see the man page for
	  iptables(8).  This table is used for various packet alterations
	  which can effect how the packet is routed.

	  To compile it as a module, choose M here.  If unsure, say N.

config IP_NF_TARGET_TOS
	tristate "TOS target support"
	depends on IP_NF_MANGLE
	help
	  This option adds a `TOS' target, which allows you to create rules in
	  the `mangle' table which alter the Type Of Service field of an IP
	  packet prior to routing.

	  To compile it as a module, choose M here.  If unsure, say N.

config IP_NF_TARGET_ECN
	tristate "ECN target support"
	depends on IP_NF_MANGLE
	---help---
	  This option adds a `ECN' target, which can be used in the iptables mangle
	  table.  

	  You can use this target to remove the ECN bits from the IPv4 header of
	  an IP packet.  This is particularly useful, if you need to work around
	  existing ECN blackholes on the internet, but don't want to disable
	  ECN support in general.

	  To compile it as a module, choose M here.  If unsure, say N.

config IP_NF_TARGET_DSCP
	tristate "DSCP target support"
	depends on IP_NF_MANGLE
	help
	  This option adds a `DSCP' match, which allows you to match against
	  the IPv4 header DSCP field (DSCP codepoint).

	  The DSCP codepoint can have any value between 0x0 and 0x4f.

	  To compile it as a module, choose M here.  If unsure, say N.

config IP_NF_TARGET_TTL
	tristate  'TTL target support'
	depends on IP_NF_MANGLE
	help
	  This option adds a `TTL' target, which enables the user to modify
	  the TTL value of the IP header.

	  While it is safe to decrement/lower the TTL, this target also enables
	  functionality to increment and set the TTL value of the IP header to
	  arbitrary values.  This is EXTREMELY DANGEROUS since you can easily
	  create immortal packets that loop forever on the network.

	  To compile it as a module, choose M here.  If unsure, say N.

config IP_NF_TARGET_CLUSTERIP
	tristate "CLUSTERIP target support (EXPERIMENTAL)"
	depends on IP_NF_MANGLE && EXPERIMENTAL
	depends on (IP_NF_CONNTRACK && IP_NF_CONNTRACK_MARK) || (NF_CONNTRACK_MARK && NF_CONNTRACK_IPV4)
	help
	  The CLUSTERIP target allows you to build load-balancing clusters of
	  network servers without having a dedicated load-balancing
	  router/server/switch.
	
	  To compile it as a module, choose M here.  If unsure, say N.

# raw + specific targets
config IP_NF_RAW
	tristate  'raw table support (required for NOTRACK/TRACE)'
	depends on IP_NF_IPTABLES
	help
	  This option adds a `raw' table to iptables. This table is the very
	  first in the netfilter framework and hooks in at the PREROUTING
	  and OUTPUT chains.
	
	  If you want to compile it as a module, say M here and read
	  <file:Documentation/modules.txt>.  If unsure, say `N'.

# ARP tables
config IP_NF_ARPTABLES
	tristate "ARP tables support"
	depends on NETFILTER_XTABLES
	help
	  arptables is a general, extensible packet identification framework.
	  The ARP packet filtering and mangling (manipulation)subsystems
	  use this: say Y or M here if you want to use either of those.

	  To compile it as a module, choose M here.  If unsure, say N.

config IP_NF_ARPFILTER
	tristate "ARP packet filtering"
	depends on IP_NF_ARPTABLES
	help
	  ARP packet filtering defines a table `filter', which has a series of
	  rules for simple ARP packet filtering at local input and
	  local output.  On a bridge, you can also specify filtering rules
	  for forwarded ARP packets. See the man page for arptables(8).

	  To compile it as a module, choose M here.  If unsure, say N.

config IP_NF_ARP_MANGLE
	tristate "ARP payload mangling"
	depends on IP_NF_ARPTABLES
	help
	  Allows altering the ARP packet payload: source and destination
	  hardware and network addresses.

endmenu