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NAME | DESCRIPTION | USAGE | DIFFERENCES TO LEGACY IPTABLES | EXAMPLES | LIMITATIONS | SEE ALSO | AUTHORS | COLOPHON |
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XTABLES-NFT(8) System Manager's Manual XTABLES-NFT(8)
xtables-nft — iptables using nftables kernel api
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.
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)
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.
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.
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/ .
nft(8), xtables-translate(8), xtables-monitor(8)
The nftables framework is written by the Netfilter project
(https://www.netfilter.org).
This manual page was written by Arturo Borrero Gonzalez
<[email protected]> for the Debian project, but may be used by
others.
This documentation is free/libre under the terms of the GPLv2+.
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 2024-06-14. (At that time,
the date of the most recent commit that was found in the
repository was 2024-06-12.) 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
[email protected]
June 2018 XTABLES-NFT(8)
Pages that refer to this page: arptables-nft(8), ebtables-nft(8), xtables-legacy(8)
Copyright and license for this manual page
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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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