#
# IP netfilter configuration
#
menu "IP: Netfilter Configuration"
depends on INET && NETFILTER
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_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_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
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_QUEUE
tristate "Userspace queueing via NETLINK"
help
Netfilter has the ability to queue packets to user space: the
netlink device can be used to access them using this driver.
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)"
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 simple matches.
config IP_NF_MATCH_LIMIT
tristate "limit match support"
depends on IP_NF_IPTABLES
help
limit matching allows you to control the rate at which a rule can be
matched: mainly useful in combination with the LOG target ("LOG
target support", below) and to avoid some Denial of Service attacks.
To compile it as a module, choose M here. If unsure, say N.
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_MAC
tristate "MAC address match support"
depends on IP_NF_IPTABLES
help
MAC matching allows you to match packets based on the source
Ethernet address of the packet.
To compile it as a module, choose M here. If unsure, say N.
config IP_NF_MATCH_PKTTYPE
tristate "Packet type match support"
depends on IP_NF_IPTABLES
help
Packet type matching allows you to match a packet by
its "class", eg. BROADCAST, MULTICAST, ...
Typical usage:
iptables -A INPUT -m pkttype --pkt-type broadcast -j LOG
To compile it as a module, choose M here. If unsure, say N.
config IP_NF_MATCH_MARK
tristate "netfilter MARK match support"
depends on IP_NF_IPTABLES
help
Netfilter mark matching allows you to match packets based on the
`nfmark' value in the packet. This can be set by the MARK target
(see below).
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:
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_LENGTH
tristate "LENGTH match support"
depends on IP_NF_IPTABLES
help
This option allows you to match the length of a packet against a
specific value or range of values.
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_TCPMSS
tristate "tcpmss match support"
depends on IP_NF_IPTABLES
help
This option adds a `tcpmss' match, which allows you to examine the
MSS value of TCP SYN packets, which control the maximum packet size
for that connection.
To compile it as a module, choose M here. If unsure, say N.
config IP_NF_MATCH_HELPER
tristate "Helper match support"
depends on IP_NF_CONNTRACK && IP_NF_IPTABLES
help
Helper matching allows you to match packets in dynamic connections
tracked by a conntrack-helper, ie. ip_conntrack_ftp
To compile it as a module, choose M here. If unsure, say Y.
config IP_NF_MATCH_STATE
tristate "Connection state match support"
depends on IP_NF_CONNTRACK && IP_NF_IPTABLES
help
Connection state matching allows you to match packets based on their
relationship to a tracked connection (ie. previous packets). This
is a powerful tool for packet classification.
To compile it as a module, choose M here. If unsure, say N.
config IP_NF_MATCH_CONNTRACK
tristate "Connection tracking match support"
depends on IP_NF_CONNTRACK && IP_NF_IPTABLES
help
This is a general conntrack match module, a superset of the state match.
It allows matching on additional conntrack information, which is
useful in complex configurations, such as NAT gateways with multiple
internet links or tunnels.
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_PHYSDEV
tristate "Physdev match support"
depends on IP_NF_IPTABLES && BRIDGE_NETFILTER
help
Physdev packet matching matches against the physical bridge ports
the IP packet arrived on or will leave by.
To compile it as a module, choose M here. If unsure, say N.
# The 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_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_CONNTRACK!=y && IP_NF_IPTABLES!=y && (IP_NF_COMPAT_IPCHAINS!=y && IP_NF_COMPAT_IPFWADM || IP_NF_COMPAT_IPCHAINS) || IP_NF_IPTABLES && IP_NF_CONNTRACK && IP_NF_NAT
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_LOCAL
bool "NAT of local connections (READ HELP)"
depends on IP_NF_NAT
help
This option enables support for NAT of locally originated connections.
Enable this if you need to use destination NAT on connections
originating from local processes on the nat box itself.
Please note that you will need a recent version (>= 1.2.6a)
of the iptables userspace program in order to use this feature.
See for download instructions.
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_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_MARK
tristate "MARK target support"
depends on IP_NF_MANGLE
help
This option adds a `MARK' target, which allows you to create rules
in the `mangle' table which alter the netfilter mark (nfmark) field
associated with the packet prior to routing. This can change
the routing method (see `Use netfilter MARK value as routing
key') and can also be used by other subsystems to change their
behavior.
To compile it as a module, choose M here. If unsure, say N.
config IP_NF_TARGET_CLASSIFY
tristate "CLASSIFY target support"
depends on IP_NF_MANGLE
help
This option adds a `CLASSIFY' target, which enables the user to set
the priority of a packet. Some qdiscs can use this value for
classification, among these are:
atm, cbq, dsmark, pfifo_fast, htb, prio
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"
depends on IP_NF_IPTABLES
---help---
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
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.
config IP_NF_ARPTABLES
tristate "ARP tables support"
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.
# Backwards compatibility modules: only if you don't build in the others.
config IP_NF_COMPAT_IPCHAINS
tristate "ipchains (2.2-style) support"
depends on IP_NF_CONNTRACK!=y && IP_NF_IPTABLES!=y
help
This option places ipchains (with masquerading and redirection
support) back into the kernel, using the new netfilter
infrastructure. It is not recommended for new installations (see
`Packet filtering'). With this enabled, you should be able to use
the ipchains tool exactly as in 2.2 kernels.
To compile it as a module, choose M here. If unsure, say N.
config IP_NF_COMPAT_IPFWADM
tristate "ipfwadm (2.0-style) support"
depends on IP_NF_CONNTRACK!=y && IP_NF_IPTABLES!=y && IP_NF_COMPAT_IPCHAINS!=y
help
This option places ipfwadm (with masquerading and redirection
support) back into the kernel, using the new netfilter
infrastructure. It is not recommended for new installations (see
`Packet filtering'). With this enabled, you should be able to use
the ipfwadm tool exactly as in 2.0 kernels.
To compile it as a module, choose M here. If unsure, say N.
config IP_NF_TARGET_NOTRACK
tristate 'NOTRACK target support'
depends on IP_NF_RAW
help
The NOTRACK target allows a select rule to specify
which packets *not* to enter the conntrack/NAT
subsystem with all the consequences (no ICMP error tracking,
no protocol helpers for the selected packets).
If you want to compile it as a module, say M here and read
. If unsure, say `N'.
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
. If unsure, say `N'.
help
endmenu