# Linux Bridge Ports Stuck in Learning State on Cumulus Linux 4.x

DevFeed: [Linux Bridge Ports Stuck in Learning State on Cumulus Linux 4.x](<https://devfeed.tech/articles/weird-ports-on-linux-bridge-are-stuck-11200.md>)

Original publisher: [Read original article](<https://blog.ipspace.net/2025/06/linux-bridge-stuck-ports/>)

Published: 2025-06-05T05:23:00Z

Content type: article

Language: en

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

Topics: [Linux](<https://devfeed.tech/topics/linux.md>), [networking](<https://devfeed.tech/topics/networking.md>), [VXLAN](<https://devfeed.tech/topics/vxlan.md>), [bug](<https://devfeed.tech/topics/bug.md>), [configuration](<https://devfeed.tech/topics/configuration.md>), [BGP](<https://devfeed.tech/topics/bgp.md>)

Tags: [bgp](<https://devfeed.tech/tags/bgp.md>), [bug](<https://devfeed.tech/tags/bug.md>), [configuration](<https://devfeed.tech/tags/configuration.md>), [linux](<https://devfeed.tech/tags/linux.md>), [netlab](<https://devfeed.tech/tags/netlab.md>), [networking](<https://devfeed.tech/tags/networking.md>), [virtualization](<https://devfeed.tech/tags/virtualization.md>), [vxlan](<https://devfeed.tech/tags/vxlan.md>)

## AI overview

Integration tests for netlab 2.0 exposed intermittent VXLAN failures on Cumulus Linux 4.x. The issue was traced to Linux bridge ports remaining in the learning state when STP was disabled, with the outcome also affected by a change in module configuration order.

## Source excerpt

Just when you thought you got used to the weirdnesses in the networking implementations, you get a curveball like this one. Life is never dull if you test network devices. Before releasing netlab release 2.0, I ran the full suite of integration tests for all devices for which I have the images. Interestingly, most VXLAN tests failed for Cumulus Linux 4.x even though we haven't touched that code for ages. Next step: trying to figure out what changed. The configuration changes were minimal. Even worse, the failure was non-deterministic. Somehow, we managed to transform a Cumulus Linux 4.x VM into a Heisenberg switch. Read more ...