{ "content": [ { "type": "text", "text": "# ip6tables(8) (man)\n\n## TLDR\n\n> This command is an alias of `iptables` for the IPv6 firewall.\n\n- View documentation for the original command:\n `tldr iptables`\n\n*Source: tldr-pages*\n\n---\n\n**Summary:** iptables/ip6tables — administration tool for IPv4/IPv6 packet filtering and NAT\n\n**Synopsis:** iptables [-t table] {-A|-C|-D} chain rule-specification\nip6tables [-t table] {-A|-C|-D} chain rule-specification\niptables [-t table] -I chain [rulenum] rule-specification\niptables [-t table] -R chain rulenum rule-specification\niptables [-t table] -D chain rulenum\niptables [-t table] -S [chain [rulenum]]\niptables [-t table] {-F|-L|-Z} [chain [rulenum]] [options...]\niptables [-t table] -N chain\niptables [-t table] -X [chain]\niptables [-t table] -P chain target\niptables [-t table] -E old-chain-name new-chain-name\nrule-specification = [matches...] [target]\nmatch = -m matchname [per-match-options]\ntarget = -j targetname [per-target-options]\n\n## Flags\n\n| Flag | Long | Arg | Description |\n|------|------|-----|-------------|\n| -A | --append | — | Append one or more rules to the end of the selected chain. When the source and/or destination names resolve to more than |\n| -C | --check | — | Check whether a rule matching the specification does exist in the selected chain. This command uses the same logic as -D |\n| -D | --delete | — | |\n| -D | --delete | — | Delete one or more rules from the selected chain. There are two versions of this com‐ mand: the rule can be specified as |\n| -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 |\n| -R | --replace | — | Replace a rule in the selected chain. If the source and/or destination names resolve to multiple addresses, the command |\n| -L | --list | — | List all rules in the selected chain. If no chain is selected, all chains are listed. Like every other iptables command, |\n| -S | --list-rules | — | Print all rules in the selected chain. If no chain is selected, all chains are printed like iptables-save. Like every ot |\n| -F | --flush | — | Flush the selected chain (all the chains in the table if none is given). This is equivalent to deleting all the rules on |\n| -Z | --zero | — | 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 |\n| -N | --new-chain | — | Create a new user-defined chain by the given name. There must be no target of that name already. |\n| -X | --delete-chain | — | Delete the optional user-defined chain specified. There must be no references to the chain. If there are, you must delet |\n| -P | --policy | — | Set the policy for the built-in (non-user-defined) chain to the given target. The policy target must be either ACCEPT or |\n| -E | --rename-chain | — | Rename the user specified chain to the user supplied name. This is cosmetic, and has no effect on the structure of the t |\n| -h | — | — | PARAMETERS The following parameters make up a rule specification (as used in the add, delete, insert, replace and append |\n| -4 | --ipv4 | — | This option has no effect in iptables and iptables-restore. If a rule using the -4 option is inserted with (and only wit |\n| -6 | --ipv6 | — | If a rule using the -6 option is inserted with (and only with) iptables-restore, it will be silently ignored. Any other |\n| -m | --match | — | Specifies a match to use, that is, an extension module that tests for a specific prop‐ erty. The set of matches make up |\n| -j | --jump | — | 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 |\n| -g | --goto | — | This specifies that the processing should continue in a user specified chain. Unlike the --jump option return will not c |\n| -c | --set-counters | — | This enables the administrator to initialize the packet and byte counters of a rule (during INSERT, APPEND, REPLACE oper |\n| -v | --verbose | — | Verbose output. This option makes the list command show the interface name, the rule options (if any), and the TOS masks |\n| -w | --wait | — | Wait for the xtables lock. To prevent multiple instances of the program from running concurrently, an attempt will be ma |\n| -W | --wait-interval | — | Interval to wait per each iteration. When running latency sensitive applications, waiting for the xtables lock for exten |\n| -n | --numeric | — | Numeric output. IP addresses and port numbers will be printed in numeric format. By default, the program will try to dis |\n| -x | --exact | — | Expand numbers. Display the exact value of the packet and byte counters, instead of only the rounded number in K's (mult |\n| — | --line-numbers | — | When listing rules, add line numbers to the beginning of each rule, corresponding to that rule's position in the chain. |\n\n## See Also\n\n- iptables-apply(8)\n- iptables-save(8)\n- iptables-restore(8)\n- iptables-extensions(8)\n\n## Section Outline\n\n- **NAME** (2 lines)\n- **SYNOPSIS** (28 lines)\n- **DESCRIPTION** (8 lines)\n- **TARGETS** (10 lines)\n- **TABLES** (3 lines) — 1 subsections\n - -t --table (44 lines)\n- **OPTIONS** (9 lines) — 27 subsections\n - -A --append (4 lines)\n - -C --check (4 lines)\n - -D --delete (1 lines)\n - -D --delete (4 lines)\n - -I --insert (4 lines)\n - -R --replace (3 lines)\n - -L --list (11 lines)\n - -S --list-rules (4 lines)\n - -F --flush (3 lines)\n - -Z --zero (4 lines)\n - -N --new-chain (3 lines)\n - -X --delete-chain (5 lines)\n - -P --policy (3 lines)\n - -E --rename-chain (3 lines)\n - -h (4 lines)\n - -4 --ipv4 (5 lines)\n - -6 --ipv6 (33 lines)\n - -m --match (5 lines)\n - -j --jump (7 lines)\n - -g --goto (26 lines)\n - -c --set-counters (6 lines)\n - -v --verbose (7 lines)\n - -w --wait (6 lines)\n - -W --wait-interval (5 lines)\n - -n --numeric (4 lines)\n - -x --exact (4 lines)\n - --line-numbers (8 lines)\n- **LOCK FILE** (5 lines)\n- **MATCH AND TARGET EXTENSIONS** (3 lines)\n- **DIAGNOSTICS** (4 lines)\n- **BUGS** (2 lines)\n- **COMPATIBILITY WITH IPCHAINS** (18 lines)\n- **SEE ALSO** (7 lines)\n- **AUTHORS** (19 lines)\n- **VERSION** (5 lines)\n\n## Full Content\n\n### NAME\n\niptables/ip6tables — administration tool for IPv4/IPv6 packet filtering and NAT\n\n### SYNOPSIS\n\niptables [-t table] {-A|-C|-D} chain rule-specification\n\nip6tables [-t table] {-A|-C|-D} chain rule-specification\n\niptables [-t table] -I chain [rulenum] rule-specification\n\niptables [-t table] -R chain rulenum rule-specification\n\niptables [-t table] -D chain rulenum\n\niptables [-t table] -S [chain [rulenum]]\n\niptables [-t table] {-F|-L|-Z} [chain [rulenum]] [options...]\n\niptables [-t table] -N chain\n\niptables [-t table] -X [chain]\n\niptables [-t table] -P chain target\n\niptables [-t table] -E old-chain-name new-chain-name\n\nrule-specification = [matches...] [target]\n\nmatch = -m matchname [per-match-options]\n\ntarget = -j targetname [per-target-options]\n\n### DESCRIPTION\n\nIptables and ip6tables are used to set up, maintain, and inspect the tables of IPv4 and IPv6\npacket filter rules in the Linux kernel. Several different tables may be defined. Each ta‐\nble contains a number of built-in chains and may also contain user-defined chains.\n\nEach chain is a list of rules which can match a set of packets. Each rule specifies what to\ndo with a packet that matches. This is called a `target', which may be a jump to a user-de‐\nfined chain in the same table.\n\n### TARGETS\n\nA firewall rule specifies criteria for a packet and a target. If the packet does not match,\nthe next rule in the chain is examined; if it does match, then the next rule is specified by\nthe value of the target, which can be the name of a user-defined chain, one of the targets\ndescribed in iptables-extensions(8), or one of the special values ACCEPT, DROP or RETURN.\n\nACCEPT means to let the packet through. DROP means to drop the packet on the floor. RETURN\nmeans stop traversing this chain and resume at the next rule in the previous (calling) chain.\nIf the end of a built-in chain is reached or a rule in a built-in chain with target RETURN is\nmatched, the target specified by the chain policy determines the fate of the packet.\n\n### TABLES\n\nThere are currently five independent tables (which tables are present at any time depends on\nthe kernel configuration options and which modules are present).\n\n#### -t --table\n\nThis option specifies the packet matching table which the command should operate on.\nIf the kernel is configured with automatic module loading, an attempt will be made to\nload the appropriate module for that table if it is not already there.\n\nThe tables are as follows:\n\nfilter:\nThis is the default table (if no -t option is passed). It contains the built-in\nchains INPUT (for packets destined to local sockets), FORWARD (for packets being\nrouted through the box), and OUTPUT (for locally-generated packets).\n\nnat:\nThis table is consulted when a packet that creates a new connection is encoun‐\ntered. It consists of four built-ins: PREROUTING (for altering packets as soon as\nthey come in), INPUT (for altering packets destined for local sockets), OUTPUT\n(for altering locally-generated packets before routing), and POSTROUTING (for al‐\ntering packets as they are about to go out). IPv6 NAT support is available since\nkernel 3.7.\n\nmangle:\nThis table is used for specialized packet alteration. Until kernel 2.4.17 it had\ntwo built-in chains: PREROUTING (for altering incoming packets before routing) and\nOUTPUT (for altering locally-generated packets before routing). Since kernel\n2.4.18, three other built-in chains are also supported: INPUT (for packets coming\ninto the box itself), FORWARD (for altering packets being routed through the box),\nand POSTROUTING (for altering packets as they are about to go out).\n\nraw:\nThis table is used mainly for configuring exemptions from connection tracking in\ncombination with the NOTRACK target. It registers at the netfilter hooks with\nhigher priority and is thus called before ipconntrack, or any other IP tables.\nIt provides the following built-in chains: PREROUTING (for packets arriving via\nany network interface) OUTPUT (for packets generated by local processes)\n\nsecurity:\nThis table is used for Mandatory Access Control (MAC) networking rules, such as\nthose enabled by the SECMARK and CONNSECMARK targets. Mandatory Access Control is\nimplemented by Linux Security Modules such as SELinux. The security table is\ncalled after the filter table, allowing any Discretionary Access Control (DAC)\nrules in the filter table to take effect before MAC rules. This table provides\nthe following built-in chains: INPUT (for packets coming into the box itself),\nOUTPUT (for altering locally-generated packets before routing), and FORWARD (for\naltering packets being routed through the box).\n\n### OPTIONS\n\nThe options that are recognized by iptables and ip6tables can be divided into several differ‐\nent groups.\n\nCOMMANDS\nThese options specify the desired action to perform. Only one of them can be specified on the\ncommand line unless otherwise stated below. For long versions of the command and option\nnames, you need to use only enough letters to ensure that iptables can differentiate it from\nall other options.\n\n#### -A --append\n\nAppend one or more rules to the end of the selected chain. When the source and/or\ndestination names resolve to more than one address, a rule will be added for each pos‐\nsible address combination.\n\n#### -C --check\n\nCheck whether a rule matching the specification does exist in the selected chain. This\ncommand uses the same logic as -D to find a matching entry, but does not alter the ex‐\nisting iptables configuration and uses its exit code to indicate success or failure.\n\n#### -D --delete\n\n#### -D --delete\n\nDelete one or more rules from the selected chain. There are two versions of this com‐\nmand: the rule can be specified as a number in the chain (starting at 1 for the first\nrule) or a rule to match.\n\n#### -I --insert\n\nInsert one or more rules in the selected chain as the given rule number. So, if the\nrule number is 1, the rule or rules are inserted at the head of the chain. This is\nalso the default if no rule number is specified.\n\n#### -R --replace\n\nReplace a rule in the selected chain. If the source and/or destination names resolve\nto multiple addresses, the command will fail. Rules are numbered starting at 1.\n\n#### -L --list\n\nList all rules in the selected chain. If no chain is selected, all chains are listed.\nLike every other iptables command, it applies to the specified table (filter is the\ndefault), so NAT rules get listed by\niptables -t nat -n -L\nPlease note that it is often used with the -n option, in order to avoid long reverse\nDNS lookups. It is legal to specify the -Z (zero) option as well, in which case the\nchain(s) will be atomically listed and zeroed. The exact output is affected by the\nother arguments given. The exact rules are suppressed until you use\niptables -L -v\nor iptables-save(8).\n\n#### -S --list-rules\n\nPrint all rules in the selected chain. If no chain is selected, all chains are\nprinted like iptables-save. Like every other iptables command, it applies to the spec‐\nified table (filter is the default).\n\n#### -F --flush\n\nFlush the selected chain (all the chains in the table if none is given). This is\nequivalent to deleting all the rules one by one.\n\n#### -Z --zero\n\nZero the packet and byte counters in all chains, or only the given chain, or only the\ngiven rule in a chain. It is legal to specify the -L, --list (list) option as well, to\nsee the counters immediately before they are cleared. (See above.)\n\n#### -N --new-chain\n\nCreate a new user-defined chain by the given name. There must be no target of that\nname already.\n\n#### -X --delete-chain\n\nDelete the optional user-defined chain specified. There must be no references to the\nchain. If there are, you must delete or replace the referring rules before the chain\ncan be deleted. The chain must be empty, i.e. not contain any rules. If no argument\nis given, it will attempt to delete every non-builtin chain in the table.\n\n#### -P --policy\n\nSet the policy for the built-in (non-user-defined) chain to the given target. The\npolicy target must be either ACCEPT or DROP.\n\n#### -E --rename-chain\n\nRename the user specified chain to the user supplied name. This is cosmetic, and has\nno effect on the structure of the table.\n\n#### -h\n\nPARAMETERS\nThe following parameters make up a rule specification (as used in the add, delete, insert,\nreplace and append commands).\n\n#### -4 --ipv4\n\nThis option has no effect in iptables and iptables-restore. If a rule using the -4\noption is inserted with (and only with) ip6tables-restore, it will be silently ig‐\nnored. Any other uses will throw an error. This option allows IPv4 and IPv6 rules in a\nsingle rule file for use with both iptables-restore and ip6tables-restore.\n\n#### -6 --ipv6\n\nIf a rule using the -6 option is inserted with (and only with) iptables-restore, it\nwill be silently ignored. Any other uses will throw an error. This option allows IPv4\nand IPv6 rules in a single rule file for use with both iptables-restore and ip6tables-\nrestore. This option has no effect in ip6tables and ip6tables-restore.\n\n[!] -p, --protocol protocol\nThe protocol of the rule or of the packet to check. The specified protocol can be one\nof tcp, udp, udplite, icmp, icmpv6,esp, ah, sctp, mh or the special keyword \"all\", or\nit can be a numeric value, representing one of these protocols or a different one. A\nprotocol name from /etc/protocols is also allowed. A \"!\" argument before the protocol\ninverts the test. The number zero is equivalent to all. \"all\" will match with all\nprotocols and is taken as default when this option is omitted. Note that, in ip6ta‐\nbles, IPv6 extension headers except esp are not allowed. esp and ipv6-nonext can be\nused with Kernel version 2.6.11 or later. The number zero is equivalent to all, which\nmeans that you cannot test the protocol field for the value 0 directly. To match on a\nHBH header, even if it were the last, you cannot use -p 0, but always need -m hbh.\n\n[!] -s, --source address[/mask][,...]\nSource specification. Address can be either a network name, a hostname, a network IP\naddress (with /mask), or a plain IP address. Hostnames will be resolved once only, be‐\nfore the rule is submitted to the kernel. Please note that specifying any name to be\nresolved with a remote query such as DNS is a really bad idea. The mask can be either\nan ipv4 network mask (for iptables) or a plain number, specifying the number of 1's at\nthe left side of the network mask. Thus, an iptables mask of 24 is equivalent to\n255.255.255.0. A \"!\" argument before the address specification inverts the sense of\nthe address. The flag --src is an alias for this option. Multiple addresses can be\nspecified, but this will expand to multiple rules (when adding with -A), or will cause\nmultiple rules to be deleted (with -D).\n\n[!] -d, --destination address[/mask][,...]\nDestination specification. See the description of the -s (source) flag for a detailed\ndescription of the syntax. The flag --dst is an alias for this option.\n\n#### -m --match\n\nSpecifies a match to use, that is, an extension module that tests for a specific prop‐\nerty. The set of matches make up the condition under which a target is invoked.\nMatches are evaluated first to last as specified on the command line and work in\nshort-circuit fashion, i.e. if one extension yields false, evaluation will stop.\n\n#### -j --jump\n\nThis specifies the target of the rule; i.e., what to do if the packet matches it. The\ntarget can be a user-defined chain (other than the one this rule is in), one of the\nspecial builtin targets which decide the fate of the packet immediately, or an exten‐\nsion (see EXTENSIONS below). If this option is omitted in a rule (and -g is not\nused), then matching the rule will have no effect on the packet's fate, but the coun‐\nters on the rule will be incremented.\n\n#### -g --goto\n\nThis specifies that the processing should continue in a user specified chain. Unlike\nthe --jump option return will not continue processing in this chain but instead in the\nchain that called us via --jump.\n\n[!] -i, --in-interface name\nName of an interface via which a packet was received (only for packets entering the\nINPUT, FORWARD and PREROUTING chains). When the \"!\" argument is used before the in‐\nterface name, the sense is inverted. If the interface name ends in a \"+\", then any\ninterface which begins with this name will match. If this option is omitted, any in‐\nterface name will match.\n\n[!] -o, --out-interface name\nName of an interface via which a packet is going to be sent (for packets entering the\nFORWARD, OUTPUT and POSTROUTING chains). When the \"!\" argument is used before the in‐\nterface name, the sense is inverted. If the interface name ends in a \"+\", then any\ninterface which begins with this name will match. If this option is omitted, any in‐\nterface name will match.\n\n[!] -f, --fragment\nThis means that the rule only refers to second and further IPv4 fragments of frag‐\nmented packets. Since there is no way to tell the source or destination ports of such\na packet (or ICMP type), such a packet will not match any rules which specify them.\nWhen the \"!\" argument precedes the \"-f\" flag, the rule will only match head fragments,\nor unfragmented packets. This option is IPv4 specific, it is not available in ip6ta‐\nbles.\n\n#### -c --set-counters\n\nThis enables the administrator to initialize the packet and byte counters of a rule\n(during INSERT, APPEND, REPLACE operations).\n\nOTHER OPTIONS\nThe following additional options can be specified:\n\n#### -v --verbose\n\nVerbose output. This option makes the list command show the interface name, the rule\noptions (if any), and the TOS masks. The packet and byte counters are also listed,\nwith the suffix 'K', 'M' or 'G' for 1000, 1,000,000 and 1,000,000,000 multipliers re‐\nspectively (but see the -x flag to change this). For appending, insertion, deletion\nand replacement, this causes detailed information on the rule or rules to be printed.\n-v may be specified multiple times to possibly emit more detailed debug statements.\n\n#### -w --wait\n\nWait for the xtables lock. To prevent multiple instances of the program from running\nconcurrently, an attempt will be made to obtain an exclusive lock at launch. By de‐\nfault, the program will exit if the lock cannot be obtained. This option will make\nthe program wait (indefinitely or for optional seconds) until the exclusive lock can\nbe obtained.\n\n#### -W --wait-interval\n\nInterval to wait per each iteration. When running latency sensitive applications,\nwaiting for the xtables lock for extended durations may not be acceptable. This option\nwill make each iteration take the amount of time specified. The default interval is 1\nsecond. This option only works with -w.\n\n#### -n --numeric\n\nNumeric output. IP addresses and port numbers will be printed in numeric format. By\ndefault, the program will try to display them as host names, network names, or ser‐\nvices (whenever applicable).\n\n#### -x --exact\n\nExpand numbers. Display the exact value of the packet and byte counters, instead of\nonly the rounded number in K's (multiples of 1000) M's (multiples of 1000K) or G's\n(multiples of 1000M). This option is only relevant for the -L command.\n\n#### --line-numbers\n\nWhen listing rules, add line numbers to the beginning of each rule, corresponding to\nthat rule's position in the chain.\n\n--modprobe=command\nWhen adding or inserting rules into a chain, use command to load any necessary modules\n(targets, match extensions, etc).\n\n### LOCK FILE\n\niptables uses the /run/xtables.lock file to take an exclusive lock at launch.\n\nThe XTABLESLOCKFILE environment variable can be used to override the default setting.\n\n### MATCH AND TARGET EXTENSIONS\n\niptables can use extended packet matching and target modules. A list of these is available\nin the iptables-extensions(8) manpage.\n\n### DIAGNOSTICS\n\nVarious error messages are printed to standard error. The exit code is 0 for correct func‐\ntioning. Errors which appear to be caused by invalid or abused command line parameters cause\nan exit code of 2, and other errors cause an exit code of 1.\n\n### BUGS\n\nBugs? What's this? ;-) Well, you might want to have a look at http://bugzilla.netfilter.org/\n\n### COMPATIBILITY WITH IPCHAINS\n\nThis iptables is very similar to ipchains by Rusty Russell. The main difference is that the\nchains INPUT and OUTPUT are only traversed for packets coming into the local host and origi‐\nnating from the local host respectively. Hence every packet only passes through one of the\nthree chains (except loopback traffic, which involves both INPUT and OUTPUT chains); previ‐\nously a forwarded packet would pass through all three.\n\nThe other main difference is that -i refers to the input interface; -o refers to the output\ninterface, and both are available for packets entering the FORWARD chain.\n\nThe various forms of NAT have been separated out; iptables is a pure packet filter when using\nthe default `filter' table, with optional extension modules. This should simplify much of\nthe previous confusion over the combination of IP masquerading and packet filtering seen pre‐\nviously. So the following options are handled differently:\n-j MASQ\n-M -S\n-M -L\nThere are several other changes in iptables.\n\n### SEE ALSO\n\niptables-apply(8), iptables-save(8), iptables-restore(8), iptables-extensions(8),\n\nThe packet-filtering-HOWTO details iptables usage for packet filtering, the NAT-HOWTO details\nNAT, the netfilter-extensions-HOWTO details the extensions that are not in the standard dis‐\ntribution, and the netfilter-hacking-HOWTO details the netfilter internals.\nSee http://www.netfilter.org/.\n\n### AUTHORS\n\nRusty Russell originally wrote iptables, in early consultation with Michael Neuling.\n\nMarc Boucher made Rusty abandon ipnatctl by lobbying for a generic packet selection framework\nin iptables, then wrote the mangle table, the owner match, the mark stuff, and ran around do‐\ning cool stuff everywhere.\n\nJames Morris wrote the TOS target, and tos match.\n\nJozsef Kadlecsik wrote the REJECT target.\n\nHarald Welte wrote the ULOG and NFQUEUE target, the new libiptc, as well as the TTL, DSCP,\nECN matches and targets.\n\nThe Netfilter Core Team is: Jozsef Kadlecsik, Pablo Neira Ayuso, Eric Leblond, Florian West‐\nphal and Arturo Borrero Gonzalez. Emeritus Core Team members are: Marc Boucher, Martin\nJosefsson, Yasuyuki Kozakai, James Morris, Harald Welte and Rusty Russell.\n\nMan page originally written by Herve Eychenne .\n\n### VERSION\n\nThis manual page applies to iptables/ip6tables 1.8.7.\n\n\n\niptables 1.8.7 IPTABLES(8)\n\n" } ], "structuredContent": { "command": "ip6tables", "section": "8", "mode": "man", "summary": "iptables/ip6tables — administration tool for IPv4/IPv6 packet filtering and NAT", "synopsis": "iptables [-t table] {-A|-C|-D} chain rule-specification\nip6tables [-t table] {-A|-C|-D} chain rule-specification\niptables [-t table] -I chain [rulenum] rule-specification\niptables [-t table] -R chain rulenum rule-specification\niptables [-t table] -D chain rulenum\niptables [-t table] -S [chain [rulenum]]\niptables [-t table] {-F|-L|-Z} [chain [rulenum]] [options...]\niptables [-t table] -N chain\niptables [-t table] -X [chain]\niptables [-t table] -P chain target\niptables [-t table] -E old-chain-name new-chain-name\nrule-specification = [matches...] [target]\nmatch = -m matchname [per-match-options]\ntarget = -j targetname [per-target-options]", "tldr_summary": "This command is an alias of `iptables` for the IPv6 firewall.", "tldr_examples": [ { "description": "View documentation for the original command", "command": "tldr iptables" } ], "tldr_source": "official", "flags": [ { "flag": "-A", "long": "--append", "arg": null, "description": "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 pos‐ sible address combination." }, { "flag": "-C", "long": "--check", "arg": null, "description": "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 ex‐ isting iptables configuration and uses its exit code to indicate success or failure." }, { "flag": "-D", "long": "--delete", "arg": null, "description": "" }, { "flag": "-D", "long": "--delete", "arg": null, "description": "Delete one or more rules from the selected chain. There are two versions of this com‐ mand: the rule can be specified as a number in the chain (starting at 1 for the first rule) or a rule to match." }, { "flag": "-I", "long": "--insert", "arg": null, "description": "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." }, { "flag": "-R", "long": "--replace", "arg": null, "description": "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." }, { "flag": "-L", "long": "--list", "arg": null, "description": "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 or iptables-save(8)." }, { "flag": "-S", "long": "--list-rules", "arg": null, "description": "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 spec‐ ified table (filter is the default)." }, { "flag": "-F", "long": "--flush", "arg": null, "description": "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." }, { "flag": "-Z", "long": "--zero", "arg": null, "description": "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.)" }, { "flag": "-N", "long": "--new-chain", "arg": null, "description": "Create a new user-defined chain by the given name. There must be no target of that name already." }, { "flag": "-X", "long": "--delete-chain", "arg": null, "description": "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." }, { "flag": "-P", "long": "--policy", "arg": null, "description": "Set the policy for the built-in (non-user-defined) chain to the given target. The policy target must be either ACCEPT or DROP." }, { "flag": "-E", "long": "--rename-chain", "arg": null, "description": "Rename the user specified chain to the user supplied name. This is cosmetic, and has no effect on the structure of the table." }, { "flag": "-h", "long": null, "arg": null, "description": "PARAMETERS The following parameters make up a rule specification (as used in the add, delete, insert, replace and append commands)." }, { "flag": "-4", "long": "--ipv4", "arg": null, "description": "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 ig‐ nored. 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." }, { "flag": "-6", "long": "--ipv6", "arg": null, "description": "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 ip6ta‐ bles, 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, be‐ fore 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 multiple 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." }, { "flag": "-m", "long": "--match", "arg": null, "description": "Specifies a match to use, that is, an extension module that tests for a specific prop‐ erty. 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." }, { "flag": "-j", "long": "--jump", "arg": null, "description": "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 exten‐ sion (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 coun‐ ters on the rule will be incremented." }, { "flag": "-g", "long": "--goto", "arg": null, "description": "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 in‐ terface 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 in‐ terface 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 in‐ terface 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 in‐ terface name will match. [!] -f, --fragment This means that the rule only refers to second and further IPv4 fragments of frag‐ mented 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 ip6ta‐ bles." }, { "flag": "-c", "long": "--set-counters", "arg": null, "description": "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:" }, { "flag": "-v", "long": "--verbose", "arg": null, "description": "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 multipliers re‐ spectively (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." }, { "flag": "-w", "long": "--wait", "arg": null, "description": "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 de‐ fault, the program will exit if the lock cannot be obtained. This option will make the program wait (indefinitely or for optional seconds) until the exclusive lock can be obtained." }, { "flag": "-W", "long": "--wait-interval", "arg": null, "description": "Interval to wait per each iteration. When running latency sensitive applications, waiting for the xtables lock for extended durations may not be acceptable. This option will make each iteration take the amount of time specified. The default interval is 1 second. This option only works with -w." }, { "flag": "-n", "long": "--numeric", "arg": null, "description": "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 ser‐ vices (whenever applicable)." }, { "flag": "-x", "long": "--exact", "arg": null, "description": "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." }, { "flag": "", "long": "--line-numbers", "arg": null, "description": "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)." } ], "examples": [], "see_also": [ { "name": "iptables-apply", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/iptables-apply/8/json" }, { "name": "iptables-save", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/iptables-save/8/json" }, { "name": "iptables-restore", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/iptables-restore/8/json" }, { "name": "iptables-extensions", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/iptables-extensions/8/json" } ], "section_outline": [ { "name": "NAME", "lines": 2, "subsections": [] }, { "name": "SYNOPSIS", "lines": 28, "subsections": [] }, { "name": "DESCRIPTION", "lines": 8, "subsections": [] }, { "name": "TARGETS", "lines": 10, "subsections": [] }, { "name": "TABLES", "lines": 3, "subsections": [ { "name": "-t --table", "lines": 44, "flag": "-t", "long": "--table" } ] }, { "name": "OPTIONS", "lines": 9, "subsections": [ { "name": "-A --append", "lines": 4, "flag": "-A", "long": "--append" }, { "name": "-C --check", "lines": 4, "flag": "-C", "long": "--check" }, { "name": "-D --delete", "lines": 1, "flag": "-D", "long": "--delete" }, { "name": "-D --delete", "lines": 4, "flag": "-D", "long": "--delete" }, { "name": "-I --insert", "lines": 4, "flag": "-I", "long": "--insert" }, { "name": "-R --replace", "lines": 3, "flag": "-R", "long": "--replace" }, { "name": "-L --list", "lines": 11, "flag": "-L", "long": "--list" }, { "name": "-S --list-rules", "lines": 4, "flag": "-S", "long": "--list-rules" }, { "name": "-F --flush", "lines": 3, "flag": "-F", "long": "--flush" }, { "name": "-Z --zero", "lines": 4, "flag": "-Z", "long": "--zero" }, { "name": "-N --new-chain", "lines": 3, "flag": "-N", "long": "--new-chain" }, { "name": "-X --delete-chain", "lines": 5, "flag": "-X", "long": "--delete-chain" }, { "name": "-P --policy", "lines": 3, "flag": "-P", "long": "--policy" }, { "name": "-E --rename-chain", "lines": 3, "flag": "-E", "long": "--rename-chain" }, { "name": "-h", "lines": 4, "flag": "-h" }, { "name": "-4 --ipv4", "lines": 5, "flag": "-4", "long": "--ipv4" }, { "name": "-6 --ipv6", "lines": 33, "flag": "-6", "long": "--ipv6" }, { "name": "-m --match", "lines": 5, "flag": "-m", "long": "--match" }, { "name": "-j --jump", "lines": 7, "flag": "-j", "long": "--jump" }, { "name": "-g --goto", "lines": 26, "flag": "-g", "long": "--goto" }, { "name": "-c --set-counters", "lines": 6, "flag": "-c", "long": "--set-counters" }, { "name": "-v --verbose", "lines": 7, "flag": "-v", "long": "--verbose" }, { "name": "-w --wait", "lines": 6, "flag": "-w", "long": "--wait" }, { "name": "-W --wait-interval", "lines": 5, "flag": "-W", "long": "--wait-interval" }, { "name": "-n --numeric", "lines": 4, "flag": "-n", "long": "--numeric" }, { "name": "-x --exact", "lines": 4, "flag": "-x", "long": "--exact" }, { "name": "--line-numbers", "lines": 8, "long": "--line-numbers" } ] }, { "name": "LOCK FILE", "lines": 5, "subsections": [] }, { "name": "MATCH AND TARGET EXTENSIONS", "lines": 3, "subsections": [] }, { "name": "DIAGNOSTICS", "lines": 4, "subsections": [] }, { "name": "BUGS", "lines": 2, "subsections": [] }, { "name": "COMPATIBILITY WITH IPCHAINS", "lines": 18, "subsections": [] }, { "name": "SEE ALSO", "lines": 7, "subsections": [] }, { "name": "AUTHORS", "lines": 19, "subsections": [] }, { "name": "VERSION", "lines": 5, "subsections": [] } ] } }