ansible.builtin.iptables module – Modify iptables rules

Note

This module is part of ansible-core and included in all Ansible installations. In most cases, you can use the short module name iptables even without specifying the collections keyword. However, we recommend you use the Fully Qualified Collection Name (FQCN) ansible.builtin.iptables for easy linking to the module documentation and to avoid conflicting with other collections that may have the same module name.

Synopsis

• ansible.builtin.iptables is used to set up, maintain, and inspect the tables of IP packet filter rules in the Linux kernel.

• This module does not handle the saving and/or loading of rules, but rather only manipulates the current rules that are present in memory. This is the same as the behaviour of the iptables and ip6tables command which this module uses internally.

Parameters

Parameter	Comments
action string	Whether the rule should be appended at the bottom or inserted at the top. If the rule already exists the chain will not be modified. Choices: "append" ← (default) "insert"
chain string	Specify the iptables chain to modify. This could be a user-defined chain or one of the standard iptables chains, like INPUT, FORWARD, OUTPUT, PREROUTING, POSTROUTING, SECMARK or CONNSECMARK.
chain_management boolean added in ansible-core 2.13	If true and state is present, the chain will be created if needed. If true and state is absent, the chain will be deleted if the only other parameter passed are chain and optionally table. Choices: false ← (default) true
comment string	This specifies a comment that will be added to the rule.
ctstate list / elements=string	A list of the connection states to match in the conntrack module. Possible values are INVALID, NEW, ESTABLISHED, RELATED, UNTRACKED, SNAT, DNAT. Default: []
destination string	Destination 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 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 24 is equivalent to 255.255.255.0. A ! argument before the address specification inverts the sense of the address.
destination_port string	Destination 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 first:last. If the first port is omitted, ‘0’ is assumed; if the last is omitted, ‘65535’ is assumed. If the first port is greater than the second one they will be swapped. This is only valid if the rule also specifies one of the following protocols: tcp, udp, dccp or sctp.
destination_ports list / elements=string added in ansible-core 2.11	This specifies multiple destination port numbers or port ranges to match in the multiport module. It can only be used in conjunction with the protocols tcp, udp, udplite, dccp and sctp. Default: []
dst_range string added in Ansible 2.8	Specifies the destination IP range to match in the iprange module.
flush boolean	Flushes the specified table and chain of all rules. If no chain is specified then the entire table is purged. Ignores all other parameters. Choices: false ← (default) true
fragment string	This means that the rule only refers to second and further 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 fragment argument, the rule will only match head fragments, or unfragmented packets.
gateway string added in Ansible 2.8	This specifies the IP address of the host to send the cloned packets. This option is only valid when jump=TEE.
gid_owner string added in Ansible 2.9	Specifies the GID or group to use in the match by owner rule.
goto string	This specifies that the processing should continue in a user-specified chain. Unlike the jump argument return will not continue processing in this chain but instead in the chain that called us via jump.
icmp_type string	This allows specification of the ICMP type, which can be a numeric ICMP type, type/code pair, or one of the ICMP type names shown by the command iptables -p icmp -h.
in_interface string	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.
ip_version string	Which version of the IP protocol this rule should apply to. Choices: "ipv4" ← (default) "ipv6"
jump string	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 that decide the fate of the packet immediately, or an extension (see EXTENSIONS below). If this option is omitted in a rule (and the goto parameter 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.
limit string	Specifies the maximum average number of matches to allow per second. The number can specify units explicitly, using /second, /minute, /hour or /day, or parts of them (so 5/second is the same as 5/s).
limit_burst string	Specifies the maximum burst before the above limit kicks in.
log_level string added in Ansible 2.8	Logging level according to the syslogd-defined priorities. The value can be strings or numbers from 1-8. This parameter is only applicable if jump=LOG. Choices: "0" "1" "2" "3" "4" "5" "6" "7" "emerg" "alert" "crit" "error" "warning" "notice" "info" "debug"
log_prefix string	Specifies a log text for the rule. Only makes sense with a LOG jump.
match list / elements=string	Specifies a match to use, that is, an extension module that tests for a specific property. The set of matches makes up the condition under which a target is invoked. Matches are evaluated first to last if specified as an array and work in short-circuit fashion, in other words if one extension yields false, the evaluation will stop. Default: []
match_set string added in ansible-core 2.11	Specifies a set name that can be defined by ipset. Must be used together with the match_set_flags parameter. When the ! argument is prepended then it inverts the rule. Uses the iptables set extension.
match_set_flags string added in ansible-core 2.11	Specifies the necessary flags for the match_set parameter. Must be used together with the match_set parameter. Uses the iptables set extension. Choices dst,dst and src,src added in version 2.17. Choices: "src" "dst" "src,dst" "dst,src" "dst,dst" "src,src"
numeric boolean added in ansible-core 2.15	This parameter controls the running of the list -action of iptables, which is used internally by the module. Does not affect the actual functionality. Use this if iptables hang when creating a chain or altering policy. If true, then iptables skips the DNS-lookup of the IP addresses in a chain when it uses the list -action. Listing is used internally for example when setting a policy or creating a chain. Choices: false ← (default) true
out_interface string	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.
policy string	Set the policy for the chain to the given target. Only built-in chains can have policies. This parameter requires the chain parameter. If you specify this parameter, all other parameters will be ignored. This parameter is used to set the default policy for the given chain. Do not confuse this with jump parameter. Choices: "ACCEPT" "DROP" "QUEUE" "RETURN"
protocol string	The protocol of the rule or of the packet to check. The specified protocol can be one of tcp, udp, udplite, icmp, ipv6-icmp or icmpv6, esp, ah, sctp 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.
reject_with string	Specifies the error packet type to return while rejecting. It implies jump=REJECT.
rule_num string	Insert the rule as the given rule number. This works only with action=insert.
set_counters string	This enables the administrator to initialize the packet and byte counters of a rule (during INSERT, APPEND, REPLACE operations).
set_dscp_mark string	This allows specifying a DSCP mark to be added to packets. It takes either an integer or hex value. If the parameter is set, jump is set to DSCP. Mutually exclusive with set_dscp_mark_class.
set_dscp_mark_class string	This allows specifying a predefined DiffServ class which will be translated to the corresponding DSCP mark. If the parameter is set, jump is set to DSCP. Mutually exclusive with set_dscp_mark.
source string	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 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 24 is equivalent to 255.255.255.0. A ! argument before the address specification inverts the sense of the address.
source_port string	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 first:last. If the first port is omitted, 0 is assumed; if the last is omitted, 65535 is assumed. If the first port is greater than the second one they will be swapped.
src_range string added in Ansible 2.8	Specifies the source IP range to match the iprange module.
state string	Whether the rule should be absent or present. Choices: "absent" "present" ← (default)
syn string	This allows matching packets that have the SYN bit set and the ACK and RST bits unset. When negated, this matches all packets with the RST or the ACK bits set. Choices: "ignore" ← (default) "match" "negate"
table string	This option specifies the packet matching table on which the command should operate. 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. Choices: "filter" ← (default) "nat" "mangle" "raw" "security"
tcp_flags dictionary	TCP flags specification. tcp_flags expects a dict with the two keys flags and flags_set.
flags list / elements=string	List of flags you want to examine.
flags_set list / elements=string	Flags to be set.
to_destination string	This specifies a destination address to use with ctstate=DNAT. Without this, the destination address is never altered.
to_ports string	This specifies a destination port or range of ports to use, without this, the destination port is never altered. This is only valid if the rule also specifies one of the protocol tcp, udp, dccp or sctp.
to_source string	This specifies a source address to use with ctstate=SNAT. Without this, the source address is never altered.
uid_owner string	Specifies the UID or username to use in the match by owner rule. From Ansible 2.6 when the ! argument is prepended then the it inverts the rule to apply instead to all users except that one specified.
wait string added in ansible-base 2.10	Wait N seconds for the xtables lock to prevent multiple instances of the program from running concurrently.

Attributes

Attribute	Support	Description
check_mode	Support: full	Can run in check_mode and return changed status prediction without modifying target, if not supported the action will be skipped.
diff_mode	Support: none	Will return details on what has changed (or possibly needs changing in check_mode), when in diff mode
platform	Platform: linux	Target OS/families that can be operated against

Notes

Note

• This module just deals with individual rules. If you need advanced chaining of rules the recommended way is to template the iptables restore file.

Examples

- name: Block specific IP
  ansible.builtin.iptables:
    chain: INPUT
    source: 8.8.8.8
    jump: DROP
  become: yes

- name: Forward port 80 to 8600
  ansible.builtin.iptables:
    table: nat
    chain: PREROUTING
    in_interface: eth0
    protocol: tcp
    match: tcp
    destination_port: 80
    jump: REDIRECT
    to_ports: 8600
    comment: Redirect web traffic to port 8600
  become: yes

- name: Allow related and established connections
  ansible.builtin.iptables:
    chain: INPUT
    ctstate: ESTABLISHED,RELATED
    jump: ACCEPT
  become: yes

- name: Allow new incoming SYN packets on TCP port 22 (SSH)
  ansible.builtin.iptables:
    chain: INPUT
    protocol: tcp
    destination_port: 22
    ctstate: NEW
    syn: match
    jump: ACCEPT
    comment: Accept new SSH connections.

- name: Match on IP ranges
  ansible.builtin.iptables:
    chain: FORWARD
    src_range: 192.168.1.100-192.168.1.199
    dst_range: 10.0.0.1-10.0.0.50
    jump: ACCEPT

- name: Allow source IPs defined in ipset "admin_hosts" on port 22
  ansible.builtin.iptables:
    chain: INPUT
    match_set: admin_hosts
    match_set_flags: src
    destination_port: 22
    jump: ALLOW

- name: Tag all outbound tcp packets with DSCP mark 8
  ansible.builtin.iptables:
    chain: OUTPUT
    jump: DSCP
    table: mangle
    set_dscp_mark: 8
    protocol: tcp

- name: Tag all outbound tcp packets with DSCP DiffServ class CS1
  ansible.builtin.iptables:
    chain: OUTPUT
    jump: DSCP
    table: mangle
    set_dscp_mark_class: CS1
    protocol: tcp

# Create the user-defined chain ALLOWLIST
- iptables:
    chain: ALLOWLIST
    chain_management: true

# Delete the user-defined chain ALLOWLIST
- iptables:
    chain: ALLOWLIST
    chain_management: true
    state: absent

- name: Insert a rule on line 5
  ansible.builtin.iptables:
    chain: INPUT
    protocol: tcp
    destination_port: 8080
    jump: ACCEPT
    action: insert
    rule_num: 5

# Think twice before running following task as this may lock target system
- name: Set the policy for the INPUT chain to DROP
  ansible.builtin.iptables:
    chain: INPUT
    policy: DROP

- name: Reject tcp with tcp-reset
  ansible.builtin.iptables:
    chain: INPUT
    protocol: tcp
    reject_with: tcp-reset
    ip_version: ipv4

- name: Set tcp flags
  ansible.builtin.iptables:
    chain: OUTPUT
    jump: DROP
    protocol: tcp
    tcp_flags:
      flags: ALL
      flags_set:
        - ACK
        - RST
        - SYN
        - FIN

- name: Iptables flush filter
  ansible.builtin.iptables:
    chain: "{{ item }}"
    flush: yes
  with_items:  [ 'INPUT', 'FORWARD', 'OUTPUT' ]

- name: Iptables flush nat
  ansible.builtin.iptables:
    table: nat
    chain: '{{ item }}'
    flush: yes
  with_items: [ 'INPUT', 'OUTPUT', 'PREROUTING', 'POSTROUTING' ]

- name: Log packets arriving into an user-defined chain
  ansible.builtin.iptables:
    chain: LOGGING
    action: append
    state: present
    limit: 2/second
    limit_burst: 20
    log_prefix: "IPTABLES:INFO: "
    log_level: info

- name: Allow connections on multiple ports
  ansible.builtin.iptables:
    chain: INPUT
    protocol: tcp
    destination_ports:
      - "80"
      - "443"
      - "8081:8083"
    jump: ACCEPT

Authors

• Linus Unnebäck (@LinusU)

• Sébastien DA ROCHA (@sebastiendarocha)

Collection links

• Issue Tracker
• Repository (Sources)
• Communication