iptables 命令详解

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iptables 命令安装:


-bash/zsh: iptables: command not found

# Windows (WSL2)
sudo apt-get update sudo apt-get install iptables

# Debian
apt-get install iptables

# Ubuntu
apt-get install iptables

# Alpine
apk add iptables

# Arch Linux
pacman -S iptables

# Kali Linux
apt-get install iptables

# CentOS
yum install iptables

# Fedora
dnf install iptables

# Raspbian
apt-get install iptables

# Dockerfile
dockerfile.run/iptables

# Docker
docker run cmd.cat/iptables iptables

iptables 命令补充说明:


iptables 是 Linux 操作系统上用于配置 IPv4 数据包过滤规则的工具。它是一个强大的防火墙工具,可以用于设置网络规则、进行地址转换(NAT)、数据包修改等。

iptables 命令语法:


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]

iptables 命令选项:


       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 ipta‐
              bles configuration and uses its exit code to indicate success 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 to put both 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 to put both 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 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.

       -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  evalu‐
              ated 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 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  suf‐
              fix  'K',  'M'  or  'G'  for  1000, 1,000,000 and 1,000,000,000 multipliers 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 [seconds]
              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 pro‐
              gram 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.

       -W, --wait-interval microseconds
              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.

       -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 (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).

iptables 命令实例:


iptables 查看过滤器表的链、规则和数据包/字节计数器:

sudo iptables -vnL

iptables 清除所有规则配置:

sudo iptables -F # -F: 清除所有规则链的规则。
sudo iptables -X # -X: 删除用户自定义的链。
sudo iptables -Z # -Z: 将所有规则链的数据包和字节计数归零。

iptables 设置链策略规则:

sudo iptables -P chain rule

iptables 将规则附加到 IP 的链策略:

sudo iptables -A chain -s ip -j rule

iptables 将规则附加到考虑协议和端口的 IP 链策略:

sudo iptables -A chain -s ip -p protocol --dport port -j rule

添加 NAT 规则以将来自“192.168.0.0/24”子网的所有流量转换为主机的公共 IP:

sudo iptables -t nat -A POSTROUTING -s 192.168.0.0/24 -j MASQUERADE

iptables 删除链式法则:

sudo iptables -D chain rule_line_number

iptables 将给定表的 iptables 配置保存到文件中:

sudo iptables-save -t tablename > path/to/iptables_file

iptables 从文件恢复 iptables 配置:

sudo iptables-restore < path/to/iptables_file

iptables 命令扩展阅读:




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