[[man_de_iptables]]

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man_de_iptables [2016/03/30 15:33] (Version actuelle)
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 +==== Manuel de la commande "​iptables"​ ====
 +
 +<​code>​
 +IPTABLES(8) ​                                                 iptables 1.4.21 ​                                                ​IPTABLES(8)
 +
 +
 +
 +NAME
 +       ​iptables/​ip6tables — administration tool for IPv4/IPv6 packet filtering and NAT
 +
 +SYNOPSIS
 +       ​iptables [-t table] {-A|-C|-D} chain rule-specification
 +
 +       ​ip6tables [-t table] {-A|-C|-D} chain rule-specification
 +
 +       ​iptables [-t table] -I chain [rulenum] rule-specification
 +
 +       ​iptables [-t table] -R chain rulenum rule-specification
 +
 +       ​iptables [-t table] -D chain rulenum
 +
 +       ​iptables [-t table] -S [chain [rulenum]]
 +
 +       ​iptables [-t table] {-F|-L|-Z} [chain [rulenum]] [options...]
 +
 +       ​iptables [-t table] -N chain
 +
 +       ​iptables [-t table] -X [chain]
 +
 +       ​iptables [-t table] -P chain target
 +
 +       ​iptables [-t table] -E old-chain-name new-chain-name
 +
 +       ​rule-specification = [matches...] [target]
 +
 +       match = -m matchname [per-match-options]
 +
 +       ​target = -j targetname [per-target-options]
 +
 +DESCRIPTION
 +       ​Iptables ​ and  ip6tables ​ are  used to set up, maintain, and inspect the tables of IPv4 and 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 table.
 +
 +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  exam‐
 +       ​ined; ​ if  it  does  match, ​ then  the next rule is specified by the value of the target, which can be the name of a user-defined
 +       ​chain,​ one of the targets described in iptables-extensions(8),​ or one of the special values ACCEPT, DROP or RETURN.
 +
 +       ​ACCEPT means to let the packet through. ​ DROP means to drop the packet on the floor. ​ 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 five independent tables (which tables are present at any time depends on the kernel configuration options and
 +       which modules are present).
 +
 +       -t, --table table
 +              This  option ​ specifies ​ the  packet matching table which the command should operate on.  If the kernel is configured with
 +              automatic module loading, an attempt will be made to load the appropriate 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 destined to
 +                  local sockets), FORWARD (for packets being routed through the box), and OUTPUT (for locally-generated packets).
 +
 +              nat:
 +                  This table is consulted when a packet that creates a new connection is encountered. ​ It consists of  three  built-ins:
 +                  PREROUTING (for altering packets as soon as they come in), OUTPUT (for altering locally-generated packets before rout‐
 +                  ing), and POSTROUTING (for altering packets as they are about to go out).  IPv6 NAT support is available since  kernel
 +                  3.7.
 +
 +              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 supported: INPUT (for packets coming into the box itself), FORWARD
 +                  (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 ​ ip_conntrack, ​ or  any  other  IP
 +                  tables. ​ It provides the following built-in chains: PREROUTING (for packets arriving via any network interface) OUTPUT
 +                  (for packets generated by local processes)
 +
 +              security:
 +                  This table is used for Mandatory Access Control (MAC) networking rules, such as  those  enabled ​ by  the  SECMARK ​ and
 +                  CONNSECMARK targets. ​ Mandatory Access Control is implemented by Linux Security Modules such as SELinux. ​ The security
 +                  table is called after the filter table, allowing any Discretionary Access Control (DAC) rules in the filter ​ table  to
 +                  take  effect ​ before MAC rules. ​ This table provides the following built-in chains: INPUT (for packets coming into the
 +                  box itself), OUTPUT (for altering locally-generated packets before routing), and FORWARD (for altering ​ packets ​ being
 +                  routed through the box).
 +
 +OPTIONS
 +       The options that are recognized by iptables and ip6tables can be divided into several different groups.
 +
 +   ​COMMANDS
 +       ​These ​ options ​ specify ​ the  desired ​ action ​ to perform. Only one of them can be specified on the command line unless otherwise
 +       ​stated below. For long versions of the command and option names, you need to use only enough letters to ensure that iptables ​ 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 combination.
 +
 +       -C, --check chain rule-specification
 +              Check whether a rule matching the specification does exist in the selected chain. This command uses the same logic  as  -D
 +              to  find  a matching entry, but does not alter the existing iptables configuration and uses its exit code to indicate suc‐
 +              cess or failure.
 +
 +       -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 chain [rulenum] rule-specification
 +              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 destination 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. Like every other iptables command,
 +              it applies to the specified table (filter is the default), so NAT rules get listed by
 +               ​iptables -t nat -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
 +               ​iptables -L -v
 +
 +       -S, --list-rules [chain]
 +              Print all rules in the selected chain. ​ If no chain is selected, all chains are printed ​ like  iptables-save. ​ Like  every
 +              other iptables command, it applies to the specified table (filter is the default).
 +
 +       -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 [rulenum]]
 +              Zero the packet and byte counters in all chains, or only the given chain, or only the given rule in a chain. It  is  legal
 +              to specify the -L, --list (list) option as well, to see the counters 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. ​ The chain must be  empty, ​ i.e.  not  contain ​ any
 +              rules. ​ 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 section 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).
 +
 +       -4, --ipv4
 +              This  option ​ has  no  effect ​ in iptables and iptables-restore. ​ If a rule using the -4 option is inserted with (and only
 +              with) ip6tables-restore,​ it will be silently ignored. Any other uses will throw an error. This option allows IPv4 and IPv6
 +              rules in a single rule file for use with both iptables-restore and ip6tables-restore.
 +
 +       -6, --ipv6
 +              If  a  rule  using the -6 option is inserted with (and only with) iptables-restore,​ it will be silently ignored. Any other
 +              uses will throw an error. This option allows IPv4 and IPv6 rules in a single rule file for use with both  iptables-restore
 +              and ip6tables-restore. ​ This option has no effect in ip6tables and ip6tables-restore.
 +
 +       [!] -p, --protocol protocol
 +              The  protocol ​ of  the  rule  or  of  the  packet to check. ​ The specified protocol can be one of tcp, udp, udplite, icmp,
 +              icmpv6,esp, ah, sctp, mh or the special keyword "​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. ​ A "​!"​ argument before the protocol inverts the
 +              test.  The number zero is equivalent to all. "​all"​ will match with all protocols and is taken as default when this  option
 +              is  omitted. ​ Note that, in ip6tables, IPv6 extension headers except esp are not allowed. ​ esp and ipv6-nonext can be used
 +              with Kernel version 2.6.11 or later. ​ The number zero is equivalent to all, which means that you cannot test the  protocol
 +              field  for  the value 0 directly. To match on a HBH header, even if it were the last, you cannot use -p 0, but always need
 +              -m hbh.
 +
 +       [!] -s, --source address[/​mask][,​...]
 +              Source specification. Address can be either a network name, a hostname, a network IP address (with /mask), or a  plain  IP
 +              address. ​ Hostnames ​ will  be resolved once only, before the rule is submitted to the kernel. ​ Please note that specifying
 +              any name to be resolved with a remote query such as DNS is a really bad idea.  The mask can be either an ipv4 network mask
 +              (for  iptables) ​ or  a plain number, specifying the number of 1's at the left side of the network mask.  Thus, an iptables
 +              mask of 24 is equivalent to 255.255.255.0. ​ A "​!"​ argument before the address ​ specification ​ inverts ​ the  sense  of  the
 +              address. ​ The flag --src is an alias for this option. ​ Multiple addresses can be specified, but this will expand to multi‐
 +              ple rules (when adding with -A), or will cause multiple rules to be deleted (with -D).
 +
 +       [!] -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.
 +
 +       -m, --match match
 +              Specifies ​ a match to use, that is, an extension module that tests for a specific property. The set of matches make up the
 +              condition under which a target is invoked. Matches are evaluated first to last as specified on the command line  and  work
 +              in short-circuit fashion, i.e. if one extension yields false, evaluation will stop.
 +
 +       -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 (and -g is not used), then matching the rule
 +              will have no effect on the packet'​s fate, but the counters on the rule will be incremented.
 +
 +       -g, --goto chain
 +              This specifies that the processing should continue in a user specified chain. Unlike the --jump ​ option ​ return ​ will  not
 +              continue processing in this chain but instead in the chain that called us via --jump.
 +
 +       [!] -i, --in-interface name
 +              Name of an interface via which a packet was 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, OUTPUT and POSTROUTING
 +              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.
 +
 +       [!] -f, --fragment
 +              This means that the rule only refers to second and further IPv4 fragments of fragmented packets. ​ Since there is no way to
 +              tell the source or destination ports of such a packet (or ICMP type), such a packet will not match any rules which specify
 +              them.   ​When ​ the  "​!" ​ argument precedes the "​-f"​ flag, the rule will only match head fragments, or unfragmented packets.
 +              This option is IPv4 specific, it is not available in ip6tables.
 +
 +       -c, --set-counters packets bytes
 +              This enables the administrator to initialize the packet and byte counters of a rule (during INSERT, APPEND, REPLACE opera‐
 +              tions).
 +
 +   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 multi‐
 +              pliers 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. -v may be specified multiple times to possibly emit more detailed
 +              debug statements.
 +
 +       -w, --wait
 +              Wait  for  the  xtables ​ lock.  To prevent multiple instances of the program from running concurrently,​ an attempt will be
 +              made to obtain an exclusive lock at launch. ​ By default, the program will exit if  the  lock  cannot ​ be  obtained. ​  This
 +              option will make the program wait until the exclusive lock can be obtained.
 +
 +       -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 applicable).
 +
 +       -x, --exact
 +              Expand numbers. ​ Display the exact value of the packet and byte counters, instead of only the rounded number in K'​s ​ (mul‐
 +              tiples 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 AND TARGET EXTENSIONS
 +       ​iptables ​ can  use  extended packet matching and target modules. ​ A list of these is available in the iptables-extensions(8) man‐
 +       page.
 +
 +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, you might want to have a look at http://​bugzilla.netfilter.org/​
 +
 +COMPATIBILITY WITH IPCHAINS
 +       ​This ​ iptables ​ 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 for‐
 +       ​warded 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.
 +
 +       ​The ​ various ​ forms  of NAT have been separated out; iptables is a pure packet filter when using the default `filter'​ table, with
 +       ​optional extension modules. ​ This should simplify much of the previous confusion over the  combination ​ of  IP  masquerading ​ and
 +       ​packet filtering seen previously. ​ So the following options are handled differently:​
 +        -j MASQ
 +        -M -S
 +        -M -L
 +       There are several other changes in iptables.
 +
 +SEE ALSO
 +       ​iptables-apply(8),​ iptables-save(8),​ iptables-restore(8),​ iptables-extensions(8),​
 +
 +       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 netfilter-hacking-HOWTO details ​ the  netfilter ​ inter‐
 +       nals.
 +       See http://​www.netfilter.org/​.
 +
 +AUTHORS
 +       Rusty Russell originally wrote iptables, in early consultation with Michael Neuling.
 +
 +       ​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 everywhere.
 +
 +       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, as well as the TTL, DSCP, ECN matches and targets.
 +
 +       The Netfilter Core Team is: Marc Boucher, Martin Josefsson, Yasuyuki Kozakai, Jozsef Kadlecsik, Patrick ​ McHardy, ​ James  Morris,
 +       Pablo Neira Ayuso, Harald Welte and Rusty Russell.
 +
 +       Man page originally written by Herve Eychenne <​rv@wallfire.org>​.
 +
 +VERSION
 +       This manual page applies to iptables/​ip6tables @PACKAGE_AND_VERSION@.
 +
 +
 +
 +iptables 1.4.21 ​                                                                                                             IPTABLES(8)
 +
 +</​code>​
  
  • man_de_iptables.txt
  • Dernière modification: 2016/03/30 15:33
  • (modification externe)