Main Page

Welcome to the nftables HOWTO documentation page. Here you will find documentation on how to build, install, configure and use nftables.

This documentation was initially started by Eric Leblond, known as the nftables quick HOWTO, and it has been extended and enhanced by Pablo Neira Ayuso.

If you have any suggestion to improve it, please send your comments to Netfilter users mailing list <netfilter@vger.kernel.org>.

Note that this documentation is still under development, so consider this work in progress.

Introduction

• What is nftables?
• Why nftables?
• Main differences with iptables
• Netfilter hooks and integration with existing Netfilter components.

Getting started

• Building and installing nftables from sources
• Using nftables from distributions
• Troubleshooting and FAQ
• Quick reference, nftables in 10 minutes
• Translate your iptables rules from a web app

Basic operation

• Configuring tables
• Configuring chains
• Simple rule management
• Atomic rule replacement
• Error reporting from the command line
• Building rules through expressions
• Operations at ruleset level
• Monitoring ruleset updates
• Scripting
• Ruleset debug/tracing
• Moving from iptables to nftables

Supported selectors for packet matching

• Matching packet header fields
• Matching packet metainformation
• Matching connection tracking stateful metainformation
• Rate limiting matchings
• Routing information

Possible actions on packets

• Accepting and dropping packets
• Jumping to chain
• Rejecting traffic
• Logging traffic
• Performing Network Address Translation (NAT)
• Setting packet metainformation
• Queueing to userspace
• Duplicating packets
• Mangle packet header fields
• Counters
• Load balancing
• Setting packet connection tracking metainformation

Note that, unlike iptables, you can perform several actions in one single rule.

Advanced data structures for performance packet classification

You will have to redesign your rule-set to benefit from these new nice features:

• Sets
• Dictionaries
• Intervals
• Maps
• Concatenations
• Flow tables
• Updating sets from the packet path
• Element timeouts
• Math operations
• Stateful objects

If you are already using ipset in your iptables rule-set, that transition may be a bit more simple to you.

Examples

• Simple ruleset for a workstation
• Bridge filtering
• Multiple NATs using nftables maps
• Classic perimetral firewall example

Development progress

• List of updates since Linux kernel 3.13
• Supported features compared to {ip,ip6,eb,arp}tables
• List of available translations via iptables-translate tool

Videos

• Watch Getting a grasp of nftables, thanks to NLUUG association for recording this.
• Florian Westphal - Why nftables?
• Watch Netdev 2.1 - Netfilter workshop

Thanks

To the NLnet foundation for initial sponsorship of this HOWTO: