A Practical, Task-Oriented Guide to `iproute2`

This manual serves as a comprehensive, action-based reference for the iproute2 suite, focusing on how to achieve specific networking goals rather than simply listing command flags.

🗺️ Navigation Map (Task Index)

The following table outlines the operational capabilities covered in this guide.

Category	Key Tasks & Capabilities
IP Addressing	$\text{IPv4/IPv6}$ management, filtering by interface state, adding/removing addresses, and managing primary IPs.
Neighbor Tables	ARP and NDP viewing, flushing tables, and manual entry manipulation.
Network Links	Link status, MTU changes, MAC address modification, and interface renaming.
Virtual Interfaces	Creating `VLAN`, `QinQ`, `MACVLAN`, `Dummy`, `Bonding`, and `Veth` pairs.
Link Groups	Grouping interfaces, assigning symbolic names, and bulk operations.
Bridge Management	Bridge creation, port isolation, VLAN-aware bridging, and forwarding tables.
TUN/TAP	Root/User device creation, packet format customization, and flow control.
Tunneling	`IPIP`, `SIT`, `GRE` (including p2mp), and `IPv6` tunnel management.
L2TPv3	UDP/IP tunnels, session management, and detailed status viewing.
Overlay Networks	Unicast/Multicast `VXLAN` and `GENEVE` (with custom UDP ports).
Routing	Gateway/Interface routes, Blackhole routes, Multipath, and Route Cache.
Policy Routing	Rule creation based on source/dest, ToS, firewall marks, and User IDs.
VRF & Namespaces	Virtual Routing and Forwarding, Namespace isolation, and process binding.
Multicast & Monitoring	Group management, `rtmon` logs, and real-time network event tracking.
System Config	`netconf` for viewing `sysctl` settings per interface.

🔍 Overview of `iproute2`

The iproute2 collection is the modern standard for Linux networking, designed to supersede a variety of ~~obsolete~~ legacy utilities.

Legacy vs. Modern Tooling

The transition from old tools to the new suite can be summarized as follows:

Legacy Tool	Modern `iproute2` Equivalent	Primary Purpose
`ifconfig`	`ip addr` / `ip link`	Interface & Address config
`route`	`ip route`	Routing table management
`arp`	`ip neigh`	ARP/Neighbor cache
`brctl`	`bridge` / `ip link`	Bridge configuration
`vconfig`	`ip link`	VLAN management

The Ecosystem Architecture

The toolkit is not just one command, but a suite of specialized utilities.

Key Technical Details:

Authorship: Originally developed by Alex Kuznetsov; currently maintained by Stephen Hemminger.
Installation: Typically found in packages named iproute2 or iproute.
Path Warning: The ip binary is frequently located in /sbin. Because of this, it might not be in the $PATH for non-privileged users.

📖 About this Document

"Historically, the documentation for iproute2 has been a significant pain point for users."

While the official man pages are technically accurate regarding available options, they are notoriously devoid of practical examples. This guide is designed to fill that void.

Design Philosophy

Task-Centered: Instead of a dictionary of subcommands, this guide is organized by the goal you want to achieve.
Scope: It provides deep dives into ip and bridge, and essential info on ss.
Exclusions: Due to its immense complexity, tc (Traffic Control) is considered a separate project and is not covered in this specific manual.

User Checklist for Getting Started

Verify iproute2 is installed.
Ensure you have sudo or root access (required for most commands).
Check if /sbin is in your environment path.

🛠️ Technical Conventions

Typographic Standards

inline code represents commands, flags, or file paths.
Bold text highlights critical terms.
Italics are used for emphasis or names.

Scripting & Usage

When using these tools in scripts, consider the following:

Abbreviation: Many ip commands can be shortened (e.g., ip a instead of ip addr).
Addressing: The toolkit handles both $\text{IPv4}$ and $\text{IPv6}$ seamlessly.
Consistency: Always verify the state of a link before applying routing changes.

Contributors & Legal

Last Updated: 2025-09-17

A Practical, Task-Oriented Guide to iproute2