xtables-nft(8) — Linux manual page

NAME | DESCRIPTION | USAGE | DIFFERENCES TO LEGACY IPTABLES | EXAMPLES | LIMITATIONS | SEE ALSO | AUTHORS | COLOPHON

XTABLES-NFT(8)           System Manager's Manual          XTABLES-NFT(8)

NAME         top

       xtables-nft — iptables using nftables kernel api

DESCRIPTION         top

       xtables-nft are versions of iptables that use the nftables API.
       This is a set of tools to help the system administrator migrate
       the ruleset from iptables(8), ip6tables(8), arptables(8), and
       ebtables(8) to nftables(8).

       The xtables-nft set is composed of several commands:

       • iptables-nft

       • iptables-nft-save

       • iptables-nft-restore

       • ip6tables-nft

       • ip6tables-nft-save

       • ip6tables-nft-restore

       • arptables-nft

       • ebtables-nft

         These tools use the libxtables framework extensions and hook to
         the nf_tables kernel subsystem using the nft_compat module.

USAGE         top

       The xtables-nft tools allow you to manage the nf_tables backend
       using the native syntax of iptables(8), ip6tables(8),
       arptables(8), and ebtables(8).

       You should use the xtables-nft tools exactly the same way as you
       would use the corresponding original tools.

       Adding a rule will result in that rule being added to the
       nf_tables kernel subsystem instead.  Listing the ruleset will use
       the nf_tables backend as well.

       When these tools were designed, the main idea was to replace each
       legacy binary with a symlink to the xtables-nft program, for
       example:

            /sbin/iptables -> /usr/sbin/iptables-nft-multi
            /sbin/ip6tables -> /usr/sbin/ip6tables-nft-multi
            /sbin/arptables -> /usr/sbin/arptables-nft-multi
            /sbin/ebtables -> /usr/sbin/ebtables-nft-multi

       The iptables version string will indicate whether the legacy API
       (get/setsockopt) or the new nf_tables api is used:
            iptables -V
            iptables v1.7 (nf_tables)

DIFFERENCES TO LEGACY IPTABLES         top

       Because the xtables-nft tools use the nf_tables kernel API, rule
       additions and deletions are always atomic.  Unlike iptables-
       legacy, iptables-nft -A ..  will NOT need to retrieve the current
       ruleset from the kernel, change it, and re-load the altered
       ruleset.  Instead, iptables-nft will tell the kernel to add one
       rule.  For this reason, the iptables-legacy --wait option is a
       no-op in iptables-nft.

       Use of the xtables-nft tools allow monitoring ruleset changes
       using the xtables-monitor(8) command.

       When using -j TRACE to debug packet traversal to the ruleset,
       note that you will need to use xtables-monitor(8) in --trace mode
       to obtain monitoring trace events.

EXAMPLES         top

       One basic example is creating the skeleton ruleset in nf_tables
       from the xtables-nft tools, in a fresh machine:

            root@machine:~# iptables-nft -L
            [...]
            root@machine:~# ip6tables-nft -L
            [...]
            root@machine:~# arptables-nft -L
            [...]
            root@machine:~# ebtables-nft -L
            [...]
            root@machine:~# nft list ruleset
            table ip filter {
                 chain INPUT {
                      type filter hook input priority 0; policy accept;
                 }

                 chain FORWARD {
                      type filter hook forward priority 0; policy accept;
                 }

                 chain OUTPUT {
                      type filter hook output priority 0; policy accept;
                 }
            }
            table ip6 filter {
                 chain INPUT {
                      type filter hook input priority 0; policy accept;
                 }

                 chain FORWARD {
                      type filter hook forward priority 0; policy accept;
                 }

                 chain OUTPUT {
                      type filter hook output priority 0; policy accept;
                 }
            }
            table bridge filter {
                 chain INPUT {
                      type filter hook input priority -200; policy accept;
                 }

                 chain FORWARD {
                      type filter hook forward priority -200; policy accept;
                 }

                 chain OUTPUT {
                      type filter hook output priority -200; policy accept;
                 }
            }
            table arp filter {
                 chain INPUT {
                      type filter hook input priority 0; policy accept;
                 }

                 chain FORWARD {
                      type filter hook forward priority 0; policy accept;
                 }

                 chain OUTPUT {
                      type filter hook output priority 0; policy accept;
                 }
            }

       (please note that in fresh machines, listing the ruleset for the
       first time results in all tables an chain being created).

       To migrate your complete filter ruleset, in the case of
       iptables(8), you would use:

            root@machine:~# iptables-legacy-save > myruleset # reads from x_tables
            root@machine:~# iptables-nft-restore myruleset   # writes to nf_tables
       or
            root@machine:~# iptables-legacy-save | iptables-translate-restore | less

       to see how rules would look like in the nft nft(8) syntax.

LIMITATIONS         top

       You should use Linux kernel >= 4.17.

       The CLUSTERIP target is not supported.

       To get up-to-date information about this, please head to
       http://wiki.nftables.org/ .

SEE ALSO         top

       nft(8), xtables-translate(8), xtables-monitor(8)

AUTHORS         top

       The nftables framework is written by the Netfilter project
       (https://www.netfilter.org).

       This manual page was written by Arturo Borrero Gonzalez
       <arturo@debian.org> for the Debian project, but may be used by
       others.

       This documentation is free/libre under the terms of the GPLv2+.

COLOPHON         top

       This page is part of the iptables (administer and maintain packet
       filter rules) project.  Information about the project can be
       found at ⟨http://www.netfilter.org/⟩.  If you have a bug report
       for this manual page, see ⟨http://bugzilla.netfilter.org/⟩.  This
       page was obtained from the project's upstream Git repository
       ⟨git://git.netfilter.org/iptables⟩ on 2021-04-01.  (At that time,
       the date of the most recent commit that was found in the
       repository was 2021-03-09.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to
       man-pages@man7.org

                                June 2018                 XTABLES-NFT(8)

Pages that refer to this page: arptables-nft(8)ebtables-nft(8)xtables-legacy(8)