Where NFT is Used

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Introduction

nftables is a new packet filtering framework that aims to replace the existing ip[tables] infrastructure in the Linux kernel. nftables’ design goals are quite simple, but distinct from those of its predecessor. Specifically, the goals are: easy maintainability, highly reusable in-kernel code, and extensibility via netlink. From a user point of view, we strive for a more consistent and understandable syntax for ruleset specifications. To archive this, we are designing a meta language that is used to describe how rules should be specified as well as how to interpret them

nft userland example

Nftables is a new packet filter framework that aims to replace the existing ip[tables] infrastructure in the Linux kernel.

Nftables is a generalization of the existing iptables framework, with improvements over it in functionality, performance and scalability.

nft is a new packet filter framework that aims to replace the existing ip[tables] infrastructure in the Linux kernel.

Nftables is a packet filtering framework. It replaces the existing ip[tables] infrastructure in the Linux kernel, which allows you to filter network packets through rulesets. Nftables was written by Alexei Starovoitov and is supported by Netfilter (the “netfilter” project).

The nft command has a syntax similar to iptables: it uses chains and rulesets, with some exceptions such as tables, targets, hooks and conditions. As you may have guessed from its name, nftables uses a different type of table to manage the flows; instead of containing IP addresses like iptables does for IPv4 packets or port numbers for TCP connections on UDP ports for example, each flow in nftables contains only one thing: an arbitrary amount of bytes from any protocol (IPv4 headers = 1 byte per 4 octets; ARP header = 2 bytes per 32 bits). This means you can use ANY kind of field as part of your rule conditions!

nft’s design goals are quite simple, but distinct from those of its predecessor.

nftables is a new packet filter framework that aims to replace the existing ip[tables] infrastructure in the Linux kernel. nftables has been available as an experimental feature for some time, but it became part of the standard Linux kernel release starting with version 3.7 (released in January 2012).

The main design goals of nftables are quite simple, but distinct from those of its predecessor:

  • To provide stateful packet filtering based on set-associative tables; this allows complex filtering rules and actions to be applied accurately and efficiently at wire speed.
  • To support multiple protocols (IPv4, IPv6/ICMPv6) and address families (e.g., IPv4), which was not always possible with iptables or earlier versions of ipchains due to limitations in the underlying technologies (e.g., Netfilter).

Specifically, the goals are: easy maintainability, highly reusable in-kernel code, and extensibility via netlink.

The DDoS attacks of 2019 have been well-publicized, but it’s worth noting that they were not the first time an attacker has used NFTs to target a Linux server. In fact, there are several examples in which NFTs were used in the past year or so to attack servers:

The most obvious use case is to extend existing functionality through netlink. This allows you to write your own device drivers without having any knowledge about how the kernel works. You can then make use of whatever features you need by adding new protocol families and/or actions into these subsystems.

From a user point of view, we strive for a more consistent and understandable syntax for ruleset specifications.

Nftables is a new packet filtering framework that aims to replace the existing ip[tables] infrastructure in the Linux kernel. Nftables’ design goals are quite simple, but distinct from those of its predecessor:

  • The syntax and semantics of nftables should be much more consistent with each other. A basic rule set written for nftables should be able to handle all scenarios without requiring additional rules or tweaking of existing ones.
  • Nftables supports multiple table inheritance and direct class manipulation, which makes it easier to write complex rule sets without duplicating code or having unevenly structured rulesets.
  • Nftables has many built-in functions for performing actions on packets (such as matching against various field types). This allows us to reduce the number of custom patches required by users and upstreams to add support for different protocols into our system if they want them (e.g., doing protocol parsing before passing them into nft_flow_table); also makes coding faster because we don’t have rewrite same code over again just because there is an extra field related feature which needs a specific function call such as adding timestamps on every packet but only need one call for setting up timestamps inside flow table instead doing this in every place where packets are processed like ipvsadm does today!

To archive this, we are designing a meta language that is used to describe how rules should be specified as well as how to interpret them.

The nftables packet filtering framework is a replacement for iptables. It’s more efficient, flexible and secure than the older tools.

It can be used in many places, but I want to focus on one main application: network firewall configuration. In this blog post we will talk about how we can use nftables as an alternative to iptables for configuring firewalls on Linux systems.

The first step is defining what kind of firewall rules you want to have:

nftables can be used to better organize your network

nftables is a new packet filter framework that aims to replace the existing ip[tables] infrastructure in the Linux kernel. nftables is a netfilter subsystem that is used to configure the network packet filtering ruleset. In this article, you will learn how to use it for better organizing your network.

Conclusion

This blog post has given you a brief introduction to nftables, the new packet filtering framework in the Linux kernel. It’s been designed to replace the existing ip[tables] infrastructure, which has been around since 2003. Nftables’ design goals are quite simple but distinct from those of its predecessor: easy maintainability, highly reusable in-kernel code and extensibility via netlink. From a user point of view, we strive for a more consistent and understandable syntax for ruleset specifications. To archive this, we are designing a meta language that is used to describe how rules should be specified as well as how to interpret them

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