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IP6TABLES(8)							  IP6TABLES(8)

NAME
       ip6tables - IPv6 packet filter administration

SYNOPSIS
       ip6tables [-t table] -[AD] chain rule-specification [options]
       ip6tables [-t table] -I chain [rulenum] rule-specification [options]
       ip6tables [-t table] -R chain rulenum rule-specification [options]
       ip6tables [-t table] -D chain rulenum [options]
       ip6tables [-t table] -[LFZ] [chain] [options]
       ip6tables [-t table] -N chain
       ip6tables [-t table] -X [chain]
       ip6tables [-t table] -P chain target [options]
       ip6tables [-t table] -E old-chain-name new-chain-name

DESCRIPTION
       Ip6tables  is  used to set up, maintain, and inspect the tables of IPv6
       packet filter rules in the Linux kernel.	 Several different tables  may
       be  defined.   Each  table contains a number of built-in chains and may
       also contain user-defined chains.

       Each chain is a list of rules which can match a set of  packets.	  Each
       rule specifies what to do with a packet that matches.  This is called a
       `target', which may be a jump to a user-defined chain in the  same  ta‐
       ble.

TARGETS
       A  firewall rule specifies criteria for a packet, and a target.	If the
       packet does not match, the next rule in the chain is the	 examined;  if
       it does match, then the next rule is specified by the value of the tar‐
       get, which can be the name of a user-defined chain or one of  the  spe‐
       cial values ACCEPT, DROP, QUEUE, or RETURN.

       ACCEPT  means to let the packet through.	 DROP means to drop the packet
       on the floor.  QUEUE means to pass the packet to userspace.   (How  the
       packet can be received by a userspace process differs by the particular
       queue handler.  2.4.x and  2.6.x	 kernels  up  to  2.6.13  include  the
       ip_queue	 queue handler.	 Kernels 2.6.14 and later additionally include
       the nfnetlink_queue queue handler.  Packets with a target of QUEUE will
       be  sent	 to queue number '0' in this case. Please also see the NFQUEUE
       target as described  later  in  this  man  page.)   RETURN  means  stop
       traversing  this	 chain	and  resume  at	 the next rule in the previous
       (calling) chain.	 If the end of a built-in chain is reached or  a  rule
       in a built-in chain with target RETURN is matched, the target specified
       by the chain policy determines the fate of the packet.

TABLES
       There are currently two independent tables (which tables are present at
       any  time depends on the kernel configuration options and which modules
       are present), as nat table has not been implemented yet.

       -t, --table table
	      This option specifies the packet matching table which  the  com‐
	      mand  should operate on.	If the kernel is configured with auto‐
	      matic module loading, an attempt will be made to load the appro‐
	      priate module for that table if it is not already there.

	      The tables are as follows:

	      filter:
		  This	is  the default table (if no -t option is passed).  It
		  contains the built-in chains INPUT (for packets coming  into
		  the  box  itself), FORWARD (for packets being routed through
		  the box), and OUTPUT (for locally-generated packets).

	      mangle:
		  This table is used for specialized packet alteration.	 Until
		  kernel  2.4.17  it  had two built-in chains: PREROUTING (for
		  altering incoming packets before routing)  and  OUTPUT  (for
		  altering  locally-generated  packets before routing).	 Since
		  kernel 2.4.18, three other built-in  chains  are  also  sup‐
		  ported: INPUT (for packets coming into the box itself), FOR‐
		  WARD (for altering packets being routed  through  the	 box),
		  and  POSTROUTING  (for altering packets as they are about to
		  go out).

	      raw:
		  This table is used mainly for	 configuring  exemptions  from
		  connection  tracking in combination with the NOTRACK target.
		  It registers at the netfilter hooks with higher priority and
		  is thus called before nf_conntrack, or any other IP6 tables.
		  It provides the following built-in chains:  PREROUTING  (for
		  packets  arriving  via  any  network	interface) OUTPUT (for
		  packets generated by local processes)

OPTIONS
       The options that are recognized by ip6tables can be divided  into  sev‐
       eral different groups.

   COMMANDS
       These options specify the specific action to perform.  Only one of them
       can be specified on the command line unless otherwise specified	below.
       For  all the long versions of the command and option names, you need to
       use only enough letters to ensure that ip6tables can  differentiate  it
       from all other options.

       -A, --append chain rule-specification
	      Append one or more rules to the end of the selected chain.  When
	      the source and/or destination names resolve  to  more  than  one
	      address, a rule will be added for each possible address combina‐
	      tion.

       -D, --delete chain rule-specification
       -D, --delete chain rulenum
	      Delete one or more rules from the selected chain.	 There are two
	      versions	of this command: the rule can be specified as a number
	      in the chain (starting at 1 for the first rule)  or  a  rule  to
	      match.

       -I, --insert
	      Insert one or more rules in the selected chain as the given rule
	      number.  So, if the rule number is 1,  the  rule	or  rules  are
	      inserted	at the head of the chain.  This is also the default if
	      no rule number is specified.

       -R, --replace chain rulenum rule-specification
	      Replace a rule in the selected chain.  If the source and/or des‐
	      tination	names  resolve to multiple addresses, the command will
	      fail.  Rules are numbered starting at 1.

       -L, --list [chain]
	      List all rules in the selected chain.  If no chain is  selected,
	      all  chains  are	listed.	  As  every other iptables command, it
	      applies to the specified table (filter is the default), so  man‐
	      gle rules get listed by
	       ip6tables -t mangle -n -L
	      Please  note  that it is often used with the -n option, in order
	      to avoid long reverse DNS lookups.  It is legal to  specify  the
	      -Z  (zero)  option  as  well, in which case the chain(s) will be
	      atomically listed and zeroed.  The exact output is  affected  by
	      the  other arguments given. The exact rules are suppressed until
	      you use
	       ip6tables -L -v

       -F, --flush [chain]
	      Flush the selected chain (all the chains in the table if none is
	      given).	This  is  equivalent  to deleting all the rules one by
	      one.

       -Z, --zero [chain]
	      Zero the packet and byte counters in all chains.	It is legal to
	      specify  the  -L, --list (list) option as well, to see the coun‐
	      ters immediately before they are cleared. (See above.)

       -N, --new-chain chain
	      Create a new user-defined chain by the given name.   There  must
	      be no target of that name already.

       -X, --delete-chain [chain]
	      Delete the optional user-defined chain specified.	 There must be
	      no references to the chain.  If there are, you  must  delete  or
	      replace the referring rules before the chain can be deleted.  If
	      no argument is given, it	will  attempt  to  delete  every  non-
	      builtin chain in the table.

       -P, --policy chain target
	      Set  the policy for the chain to the given target.  See the sec‐
	      tion TARGETS for the legal targets.   Only  built-in  (non-user-
	      defined)	chains	can  have  policies,  and neither built-in nor
	      user-defined chains can be policy targets.

       -E, --rename-chain old-chain new-chain
	      Rename the user specified chain to the user supplied name.  This
	      is cosmetic, and has no effect on the structure of the table.

       -h     Help.   Give a (currently very brief) description of the command
	      syntax.

   PARAMETERS
       The following parameters make up a rule specification (as used  in  the
       add, delete, insert, replace and append commands).

       -p, --protocol [!] protocol
	      The  protocol of the rule or of the packet to check.  The speci‐
	      fied protocol can be one of tcp, udp, icmpv6, esp,  all,	or  it
	      can be a numeric value, representing one of these protocols or a
	      different one. A	protocol  name	from  /etc/protocols  is  also
	      allowed.	But IPv6 extension headers except esp are not allowed.
	      esp, and ipv6-nonext can be used with Kernel version  2.6.11  or
	      later.   A  "!"  argument	 before the protocol inverts the test.
	      The number zero is equivalent to all.  Protocol all  will	 match
	      with  all	 protocols and is taken as default when this option is
	      omitted.

       -s, --source [!] address[/mask]
	      Source specification.  Address can be either a hostname  (please
	      note that specifying any name to be resolved with a remote query
	      such as DNS is a really bad idea), a network IPv6 address	 (with
	      /mask),  or  a plain IPv6 address.  (the network name isn't sup‐
	      ported now).  The mask can be either a network mask or  a	 plain
	      number,  specifying  the	number	of 1's at the left side of the
	      network  mask.   Thus,  a	 mask	of   64	  is   equivalent   to
	      ffff:ffff:ffff:ffff:0000:0000:0000:0000.	 A "!" argument before
	      the address specification inverts the sense of the address.  The
	      flag --src is an alias for this option.

       -d, --destination [!] address[/mask]
	      Destination  specification.   See	 the  description  of  the  -s
	      (source) flag for a detailed description	of  the	 syntax.   The
	      flag --dst is an alias for this option.

       -j, --jump target
	      This  specifies  the target of the rule; i.e., what to do if the
	      packet matches it.  The  target  can  be	a  user-defined	 chain
	      (other than the one this rule is in), one of the special builtin
	      targets which decide the fate of the packet immediately,	or  an
	      extension	 (see EXTENSIONS below).  If this option is omitted in
	      a rule, then matching the	 rule  will  have  no  effect  on  the
	      packet's fate, but the counters on the rule will be incremented.

       -i, --in-interface [!] name
	      Name  of an interface via which a packet is going to be received
	      (only for packets entering the  INPUT,  FORWARD  and  PREROUTING
	      chains).	 When  the  "!"	 argument is used before the interface
	      name, the sense is inverted.  If the interface name  ends	 in  a
	      "+",  then any interface which begins with this name will match.
	      If this option is omitted, any interface name will match.

       -o, --out-interface [!] name
	      Name of an interface via which a packet is going to be sent (for
	      packets  entering	 the FORWARD and OUTPUT chains).  When the "!"
	      argument is  used	 before	 the  interface	 name,	the  sense  is
	      inverted.	  If the interface name ends in a "+", then any inter‐
	      face which begins with this name will match.  If this option  is
	      omitted, any interface name will match.

       -c, --set-counters  PKTS BYTES
	      This enables the administrator to initialize the packet and byte
	      counters of a rule (during INSERT, APPEND, REPLACE operations).

   OTHER OPTIONS
       The following additional options can be specified:

       -v, --verbose
	      Verbose output.  This option makes the  list  command  show  the
	      interface	 name,	the  rule options (if any), and the TOS masks.
	      The packet and byte counters are also listed,  with  the	suffix
	      'K',  'M' or 'G' for 1000, 1,000,000 and 1,000,000,000 multipli‐
	      ers respectively (but see the -x	flag  to  change  this).   For
	      appending,  insertion,  deletion	and  replacement,  this causes
	      detailed information on the rule or rules to be printed.

       -n, --numeric
	      Numeric output.  IP addresses and port numbers will  be  printed
	      in  numeric format.  By default, the program will try to display
	      them as host names, network names, or services (whenever	appli‐
	      cable).

       -x, --exact
	      Expand  numbers.	Display the exact value of the packet and byte
	      counters, instead of only the rounded number in  K's  (multiples
	      of  1000)	 M's (multiples of 1000K) or G's (multiples of 1000M).
	      This option is only relevant for the -L command.

       --line-numbers
	      When listing rules, add line numbers to the  beginning  of  each
	      rule, corresponding to that rule's position in the chain.

       --modprobe=command
	      When adding or inserting rules into a chain, use command to load
	      any necessary modules (targets, match extensions, etc).

MATCH EXTENSIONS
       ip6tables can use extended packet matching modules.  These  are	loaded
       in  two	ways:  implicitly, when -p or --protocol is specified, or with
       the -m or --match options, followed by the matching module name;	 after
       these,  various	extra command line options become available, depending
       on the specific module.	You can specify multiple extended  match  mod‐
       ules  in	 one  line, and you can use the -h or --help options after the
       module has been specified to receive help specific to that module.

       The following are included in the base package, and most of  these  can
       be preceded by a !  to invert the sense of the match.

   ah
       This  module  matches  the parameters in Authentication header of IPsec
       packets.

       --ahspi [!] spi[:spi]
	      Matches SPI.

       --ahlen [!] length
	      Total length of this header in octets.

       --ahres
	      Matches if the reserved field is filled with zero.

   condition
       This matches if a specific /proc filename is '0' or '1'.

       --condition [!] filename
	      Match on boolean value stored in	/proc/net/ip6t_condition/file‐
	      name file

   dscp
       This module matches the 6 bit DSCP field within the TOS field in the IP
       header.	DSCP has superseded TOS within the IETF.

       --dscp value
	      Match against a numeric (decimal or hex) value [0-63].

       --dscp-class DiffServ Class
	      Match the DiffServ class. This value may be any of the  BE,  EF,
	      AFxx  or	CSx  classes.	It  will  then	be converted into it's
	      according numeric value.

   dst
       This module matches the parameters in Destination Options header

       --dst-len [!] length
	      Total length of this header in octets.

       --dst-opts type[:length][,type[:length]...]
	      numeric type of option and the length  of	 the  option  data  in
	      octets.

   esp
       This module matches the SPIs in ESP header of IPsec packets.

       --espspi [!] spi[:spi]

   eui64
       This  module matches the EUI-64 part of a stateless autoconfigured IPv6
       address.	 It compares the EUI-64 derived from the source MAC address in
       Ehternet	 frame	with the lower 64 bits of the IPv6 source address. But
       "Universal/Local" bit is not compared. This module doesn't match	 other
       link  layer  frame, and is only valid in the PREROUTING, INPUT and FOR‐
       WARD chains.

   frag
       This module matches the parameters in Fragment header.

       --fragid [!] id[:id]
	      Matches the given Identification or range of it.

       --fraglen [!] length
	      This option cannot be used with kernel version 2.6.10 or	later.
	      The  length of Fragment header is static and this option doesn't
	      make sense.

       --fragres
	      Matches if the reserved fields are filled with zero.

       --fragfirst
	      Matches on the first fragment.

       [--fragmore]
	      Matches if there are more fragments.

       [--fraglast]
	      Matches if this is the last fragement.

   fuzzy
       This module matches a rate limit based  on  a  fuzzy  logic  controller
       [FLC]

       --lower-limit number
	      Specifies the lower limit (in packets per second).

       --upper-limit number
	      Specifies the upper limit (in packets per second).

   hbh
       This module matches the parameters in Hop-by-Hop Options header

       --hbh-len [!] length
	      Total length of this header in octets.

       --hbh-opts type[:length][,type[:length]...]
	      numeric  type  of	 option	 and  the length of the option data in
	      octets.

   hl
       This module matches the Hop Limit field in the IPv6 header.

       --hl-eq [!] value
	      Matches if Hop Limit equals value.

       --hl-lt value
	      Matches if Hop Limit is less than value.

       --hl-gt value
	      Matches if Hop Limit is greater than value.

   icmpv6
       This extension is  loaded  if  `--protocol  ipv6-icmp'  or  `--protocol
       icmpv6' is specified. It provides the following option:

       --icmpv6-type [!] type[/code]|typename
	      This  allows  specification  of  the ICMPv6 type, which can be a
	      numeric ICMPv6 type, type and code, or one of  the  ICMPv6  type
	      names shown by the command
	       ip6tables -p ipv6-icmp -h

   ipv6header
       This module matches IPv6 extension headers and/or upper layer header.

       --header [!] header[,header...]
	      Matches the packet which EXACTLY includes all specified headers.
	      The headers encapsulated with  ESP  header  are  out  of	scope.
	      header  can  be  hop|hop-by-hop (Hop-by-Hop Options header), dst
	      (Destination  Options  header),  route  (Routing	header),  frag
	      (Fragment	 header),  auth (Authentication header), esp (Encapsu‐
	      lating Security Payload header), none  (No  Next	header)	 which
	      matches 59 in the 'Next Header field' of IPv6 header or any IPv6
	      extension headers, or proto which matches any upper layer proto‐
	      col  header.  A  protocol	 name  from /etc/protocols and numeric
	      value also allowed. The number 255 is equivalent to proto.

       [--soft]
	      Matches if  the  packet  includes	 all  specified	 headers  with
	      --header, AT LEAST.

   length
       This  module matches the length of the IPv6 payload in octets, or range
       of it.  IPv6 header itself isn't counted.

       --length [!] length[:length]

   limit
       This module matches at a limited rate using a token bucket  filter.   A
       rule  using  this  extension  will  match  until	 this limit is reached
       (unless the `!' flag is used).  It can be used in combination with  the
       LOG target to give limited logging, for example.

       --limit rate
	      Maximum  average	matching  rate: specified as a number, with an
	      optional `/second', `/minute', `/hour', or  `/day'  suffix;  the
	      default is 3/hour.

       --limit-burst number
	      Maximum  initial	number	of  packets to match: this number gets
	      recharged by one every time the limit  specified	above  is  not
	      reached, up to this number; the default is 5.

   mac
       --mac-source [!] address
	      Match   source   MAC   address.	 It   must   be	 of  the  form
	      XX:XX:XX:XX:XX:XX.  Note that this only makes sense for  packets
	      coming from an Ethernet device and entering the PREROUTING, FOR‐
	      WARD or INPUT chains.

   mark
       This module matches the netfilter mark field associated with  a	packet
       (which can be set using the MARK target below).

       --mark value[/mask]
	      Matches packets with the given unsigned mark value (if a mask is
	      specified, this is logically ANDed with the mask before the com‐
	      parison).

   multiport
       This  module  matches  a	 set of source or destination ports.  Up to 15
       ports can be specified.	A port range (port:port) counts as two	ports,
       but  range isn't supported now. It can only be used in conjunction with
       -p tcp or -p udp.

       --source-ports [!] port[,port[,port:port...]]
	      Match if the source port is one of the given  ports.   The  flag
	      --sports is a convenient alias for this option.

       --destination-ports [!] port[,port[,port:port...]]
	      Match  if	 the  destination port is one of the given ports.  The
	      flag --dports is a convenient alias for this option.

       --ports [!] port[,port[,port:port...]]
	      Match if the both the source and destination ports are equal  to
	      each other and to one of the given ports.

   nth
       This module matches every `n'th packet

       --every value
	      Match every `value' packet

       [--counter num]
	      Use internal counter number `num'.  Default is `0'.

       [--start num]
	      Initialize the counter at the number `num' insetad of `0'.  Most
	      between `0' and `value'-1.

       [--packet num]
	      Match on `num' packet.  Most be between `0' and `value'-1.

   owner
       This module attempts to match various  characteristics  of  the	packet
       creator, for locally-generated packets.	It is only valid in the OUTPUT
       chain, and even this some packets (such as ICMPv6 ping  responses)  may
       have  no	 owner, and hence never match.	This is regarded as experimen‐
       tal.

       --uid-owner userid
	      Matches if the packet was created by a process  with  the	 given
	      effective user id.

       --gid-owner groupid
	      Matches  if  the	packet was created by a process with the given
	      effective group id.

       --pid-owner processid
	      Matches if the packet was created by a process  with  the	 given
	      process id.

       --sid-owner sessionid
	      Matches if the packet was created by a process in the given ses‐
	      sion group.

       NOTE: pid, sid and command matching are broken on SMP

   physdev
       This module matches  on	the  bridge  port  input  and  output  devices
       enslaved	 to  a bridge device. This module is a part of the infrastruc‐
       ture that enables a transparent bridging IP firewall and is only useful
       for kernel versions above version 2.5.44.

       --physdev-in [!] name
	      Name  of	a bridge port via which a packet is received (only for
	      packets entering the INPUT, FORWARD and PREROUTING  chains).  If
	      the  interface  name  ends  in  a	 "+", then any interface which
	      begins with this name will match. If the	packet	didn't	arrive
	      through  a  bridge  device, this packet won't match this option,
	      unless '!' is used.

       --physdev-out [!] name
	      Name of a bridge port via which a packet is  going  to  be  sent
	      (for  packets  entering  the  FORWARD,  OUTPUT  and  POSTROUTING
	      chains).	If the interface name ends in a "+", then  any	inter‐
	      face  which  begins  with this name will match. Note that in the
	      nat and mangle OUTPUT chains one cannot match on the bridge out‐
	      put  port,  however  one	can in the filter OUTPUT chain. If the
	      packet won't leave by a bridge device or it is yet unknown  what
	      the  output  device  will	 be,  then the packet won't match this
	      option, unless

       [!] --physdev-is-in
	      Matches if the packet has entered through a bridge interface.

       [!] --physdev-is-out
	      Matches if the packet will leave through a bridge interface.

       [!] --physdev-is-bridged
	      Matches if the packet is being  bridged  and  therefore  is  not
	      being  routed.  This is only useful in the FORWARD and POSTROUT‐
	      ING chains.

   policy
       This modules matches the policy used by IPsec for handling a packet.

       --dir in|out
	      Used to select whether to match the policy used  for  decapsula‐
	      tion  or	the policy that will be used for encapsulation.	 in is
	      valid in the PREROUTING, INPUT and FORWARD chains, out is	 valid
	      in the POSTROUTING, OUTPUT and FORWARD chains.

       --pol none|ipsec
	      Matches if the packet is subject to IPsec processing.

       --strict
	      Selects  whether	to match the exact policy or match if any rule
	      of the policy matches the given policy.

       --reqid id
	      Matches the reqid of the policy rule. The reqid can be specified
	      with setkey(8) using unique:id as level.

       --spi spi
	      Matches the SPI of the SA.

       --proto ah|esp|ipcomp
	      Matches the encapsulation protocol.

       --mode tunnel|transport
	      Matches the encapsulation mode.

       --tunnel-src addr[/mask]
	      Matches  the source end-point address of a tunnel mode SA.  Only
	      valid with --mode tunnel.

       --tunnel-dst addr[/mask]
	      Matches the destination end-point address of a tunnel  mode  SA.
	      Only valid with --mode tunnel.

       --next Start  the next element in the policy specification. Can only be
	      used with --strict

   random
       This module randomly matches a certain percentage of all packets.

       --average percent
	      Matches the given percentage.  If omitted, a probability of  50%
	      is set.

   rt
       Match on IPv6 routing header

       --rt-type [!] type
	      Match the type (numeric).

       --rt-segsleft [!] num[:num]
	      Match the `segments left' field (range).

       --rt-len [!] length
	      Match the length of this header.

       --rt-0-res
	      Match the reserved field, too (type=0)

       --rt-0-addrs ADDR[,ADDR...]
	      Match type=0 addresses (list).

       --rt-0-not-strict
	      List of type=0 addresses is not a strict list.

   tcp
       These  extensions  are loaded if `--protocol tcp' is specified. It pro‐
       vides the following options:

       --source-port [!] port[:port]
	      Source port or port range specification. This can	 either	 be  a
	      service  name  or	 a port number. An inclusive range can also be
	      specified, using the format port:port.  If  the  first  port  is
	      omitted,	"0"  is	 assumed;  if  the last is omitted, "65535" is
	      assumed.	If the second port greater then the first they will be
	      swapped.	 The  flag  --sport  is	 a  convenient	alias for this
	      option.

       --destination-port [!] port[:port]
	      Destination port or port range specification.  The flag  --dport
	      is a convenient alias for this option.

       --tcp-flags [!] mask comp
	      Match  when  the TCP flags are as specified.  The first argument
	      is the flags which we should examine, written as	a  comma-sepa‐
	      rated list, and the second argument is a comma-separated list of
	      flags which must be set.	Flags are: SYN ACK FIN RST URG PSH ALL
	      NONE.  Hence the command
	       ip6tables -A FORWARD -p tcp --tcp-flags SYN,ACK,FIN,RST SYN
	      will  only match packets with the SYN flag set, and the ACK, FIN
	      and RST flags unset.

       [!] --syn
	      Only match TCP packets with the SYN bit set and the ACK and  RST
	      bits  cleared.   Such packets are used to request TCP connection
	      initiation; for example, blocking	 such  packets	coming	in  an
	      interface	 will  prevent	incoming TCP connections, but outgoing
	      TCP connections will be unaffected.  It is equivalent to	--tcp-
	      flags  SYN,RST,ACK  SYN.	 If the "!" flag precedes the "--syn",
	      the sense of the option is inverted.

       --tcp-option [!] number
	      Match if TCP option set.

   udp
       These extensions are loaded if `--protocol udp' is specified.  It  pro‐
       vides the following options:

       --source-port [!] port[:port]
	      Source port or port range specification.	See the description of
	      the --source-port option of the TCP extension for details.

       --destination-port [!] port[:port]
	      Destination port or port range specification.  See the  descrip‐
	      tion  of	the --destination-port option of the TCP extension for
	      details.

TARGET EXTENSIONS
       ip6tables can use extended target modules: the following	 are  included
       in the standard distribution.

   DSCP
       This  target  allows to alter the value of the DSCP bits within the TOS
       header of the IPv4 packet.  As this manipulates a packet, it  can  only
       be used in the mangle table.

       --set-dscp value
	      Set the DSCP field to a numerical value (can be decimal or hex)

       --set-dscp-class class
	      Set the DSCP field to a DiffServ class.

   HL
       This  is	 used  to  modify  the Hop Limit field in IPv6 header. The Hop
       Limit field is similar to what is known as TTL value in IPv4.   Setting
       or  incrementing the Hop Limit field can potentially be very dangerous,
       so it should be avoided at any cost. This target is only valid in  man‐
       gle table.

       Don't  ever set or increment the value on packets that leave your local
       network!

       --hl-set value
	      Set the Hop Limit to `value'.

       --hl-dec value
	      Decrement the Hop Limit `value' times.

       --hl-inc value
	      Increment the Hop Limit `value' times.

   LOG
       Turn on kernel logging of matching packets.  When this  option  is  set
       for  a rule, the Linux kernel will print some information on all match‐
       ing packets (like most IPv6 IPv6-header	fields)	 via  the  kernel  log
       (where it can be read with dmesg or syslogd(8)).	 This is a "non-termi‐
       nating target", i.e. rule traversal continues at the next rule.	So  if
       you want to LOG the packets you refuse, use two separate rules with the
       same matching criteria, first using target LOG then DROP (or REJECT).

       --log-level level
	      Level of logging (numeric or see syslog.conf(5)).

       --log-prefix prefix
	      Prefix log messages with the specified prefix; up to 29  letters
	      long, and useful for distinguishing messages in the logs.

       --log-tcp-sequence
	      Log  TCP sequence numbers. This is a security risk if the log is
	      readable by users.

       --log-tcp-options
	      Log options from the TCP packet header.

       --log-ip-options
	      Log options from the IPv6 packet header.

       --log-uid
	      Log the userid of the process which generated the packet.

   MARK
       This is used to set  the	 netfilter  mark  value	 associated  with  the
       packet.	It is only valid in the mangle table.

       --set-mark mark

   NFQUEUE
       This  target  is an extension of the QUEUE target. As opposed to QUEUE,
       it allows you to put a packet into any specific	queue,	identified  by
       its 16-bit queue number.

       --queue-num value
	      This  specifies the QUEUE number to use. Valud queue numbers are
	      0 to 65535. The default value is 0.

       It can only be used with Kernel versions	 2.6.14	 or  later,  since  it
       requires
	      the nfnetlink_queue kernel support.

   REJECT
       This  is	 used  to send back an error packet in response to the matched
       packet: otherwise it is equivalent to DROP so it is a terminating  TAR‐
       GET,  ending  rule  traversal.  This target is only valid in the INPUT,
       FORWARD and OUTPUT chains,  and	user-defined  chains  which  are  only
       called  from those chains.  The following option controls the nature of
       the error packet returned:

       --reject-with type
	      The type given can be
	       icmp6-no-route
	       no-route
	       icmp6-adm-prohibited
	       adm-prohibited
	       icmp6-addr-unreachable
	       addr-unreach
	       icmp6-port-unreachable
	       port-unreach
	      which return the appropriate ICMPv6 error message	 (port-unreach
	      is  the  default).  Finally, the option tcp-reset can be used on
	      rules which only match the TCP protocol: this causes a  TCP  RST
	      packet  to  be  sent  back.   This is mainly useful for blocking
	      ident (113/tcp) probes which frequently occur when sending  mail
	      to  broken  mail hosts (which won't accept your mail otherwise).
	      tcp-reset can only be used with kernel versions 2.6.14  or  lat‐
	      ter.

   TRACE
       This  target  has  no options.  It just turns on packet tracing for all
       packets that match this rule.

DIAGNOSTICS
       Various error messages are printed to standard error.  The exit code is
       0 for correct functioning.  Errors which appear to be caused by invalid
       or abused command line parameters cause an exit code of	2,  and	 other
       errors cause an exit code of 1.

BUGS
       Bugs?   What's  this?  ;-)  Well...  the	 counters  are not reliable on
       sparc64.

COMPATIBILITY WITH IPCHAINS
       This ip6tables is very similar to ipchains by Rusty Russell.  The  main
       difference  is  that the chains INPUT and OUTPUT are only traversed for
       packets coming into the local host and originating from the local  host
       respectively.   Hence every packet only passes through one of the three
       chains (except loopback traffic, which involves both INPUT  and	OUTPUT
       chains); previously a forwarded packet would pass through all three.

       The  other main difference is that -i refers to the input interface; -o
       refers to the output interface, and  both  are  available  for  packets
       entering	 the  FORWARD  chain.	There  are  several  other  changes in
       ip6tables.

SEE ALSO
       ip6tables-save(8), ip6tables-restore(8), iptables(8), iptables-save(8),
       iptables-restore(8), libipq(3).

       The packet-filtering-HOWTO details iptables usage for packet filtering,
       the NAT-HOWTO details NAT, the netfilter-extensions-HOWTO  details  the
       extensions  that	 are not in the standard distribution, and the netfil‐
       ter-hacking-HOWTO details the netfilter internals.
       See http://www.netfilter.org/.

AUTHORS
       Rusty Russell wrote iptables, in early consultation with Michael	 Neul‐
       ing.

       Marc  Boucher  made  Rusty  abandon  ipnatctl by lobbying for a generic
       packet selection framework in iptables, then wrote  the	mangle	table,
       the owner match, the mark stuff, and ran around doing cool stuff every‐
       where.

       James Morris wrote the TOS target, and tos match.

       Jozsef Kadlecsik wrote the REJECT target.

       Harald Welte wrote the ULOG and NFQUEUE target, the new libiptc, aswell
       as TTL match+target and libipulog.

       The  Netfilter  Core  Team  is:	Marc Boucher, Martin Josefsson, Jozsef
       Kadlecsik, James Morris, Harald Welte and Rusty Russell.

       ip6tables man page created by Andras Kis-Szabo, based on	 iptables  man
       page written by Herve Eychenne <rv@wallfire.org>.

				 Jan 22, 2006			  IP6TABLES(8)
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