# Changing Interfaces Connected to netlab Links

DevFeed: [Changing Interfaces Connected to netlab Links](<https://devfeed.tech/articles/changing-interfaces-connected-to-netlab-links-11348.md>)

Original publisher: [Read original article](<https://blog.ipspace.net/2026/03/netlab-ifindex/>)

Published: 2026-03-30T05:27:00Z

Content type: tutorial

Language: en

Sources: [ipSpace.net blog](<https://devfeed.tech/sources/ipspace-net-blog.md>)

Topics: [networking](<https://devfeed.tech/topics/networking.md>), [Containers](<https://devfeed.tech/topics/containers.md>), [virtual machines](<https://devfeed.tech/topics/virtual-machines.md>), [Cisco](<https://devfeed.tech/topics/cisco.md>)

Tags: [cisco](<https://devfeed.tech/tags/cisco.md>), [containers](<https://devfeed.tech/tags/containers.md>), [interfaces](<https://devfeed.tech/tags/interfaces.md>), [netlab](<https://devfeed.tech/tags/netlab.md>), [network](<https://devfeed.tech/tags/network.md>), [node](<https://devfeed.tech/tags/node.md>), [virtual-machines](<https://devfeed.tech/tags/virtual-machines.md>)

## AI overview

This article explains how netlab uses interface ifindex values to connect virtual lab interfaces to specific links. It examines how interface names and mappings behave across Ethernet devices, containers, KVM virtual machines, vrnetlab, and Linux processes running in containers.

## Source excerpt

Some netlab users want to accurately replicate their physical network's topology in a virtual lab. Ignoring the obvious caveats for a moment, the first hiccup is usually the interface naming. All bets are off if you're using anything but Ethernet in your actual network, but even if you did standardize on Ethernet, the container/VM interface names might not match the physical ones. netlab provided a solution for a long time - you can specify interface ifindex when attaching a node to a link. For example, use the following topology to connect Ethernet3 on R1 to Ethernet6 on R2: Read more ...