# How to configure a backup net interface

**URL:** <https://forums.linbit.com/t/how-to-configure-a-backup-net-interface/863>\
**Category:** LINSTOR\
**Created:** [June 13, 2025, 9:57am UTC](https://forums.linbit.com/t/how-to-configure-a-backup-net-interface/863 "2025-06-13T09:57:50Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![zrav](https://avatars.discourse-cdn.com/v4/letter/z/b5a626/32.png) [@zrav](https://forums.linbit.com/u/zrav)\
**Post date:** [June 13, 2025, 9:57am UTC](https://forums.linbit.com/t/how-to-configure-a-backup-net-interface/863/1 "2025-06-13T09:57:50Z")

</div>

Our small Linstor cluster is connected via a single 25G switch. Occasionally, we need to reboot this switch or perform other maintenance on the network that makes it unavailable for short periods. We’d like to setup a backup link over another 1G switch to be able to bridge this period, ideally failing over automatically and moving back to the fast link when it comes online again.  
I’ve been pouring over the documentation but I haven’t yet been able to achieve this.

I’ve created the second interface on all nodes and set the 25G interface as PrefNic:

```auto
root@node-a:~# linstor node interface list node-a
╭──────────────────────────────────────────────────────────────╮
┊ node-a ┊ NetInterface ┊ IP ┊ Port ┊ EncryptionType ┊
╞══════════════════════════════════════════════════════════════╡
┊ + ┊ backup_nic ┊ 10.77.4.2 ┊ ┊ ┊
┊ + StltCon ┊ default ┊ 10.77.3.2 ┊ 3366 ┊ PLAIN ┊
╰──────────────────────────────────────────────────────────────╯
root@node-a:~# linstor node lp node-a
╭──────────────────────────────────────────────╮
┊ Key ┊ Value ┊
╞══════════════════════════════════════════════╡
┊ Aux/NodeName ┊ node-a ┊
┊ CurStltConnName ┊ default ┊
┊ DrbdOptions/AutoEvictAllowEviction ┊ false ┊
┊ NodeUname ┊ node-a ┊
┊ PrefNic ┊ default ┊
╰──────────────────────────────────────────────╯

```

With this configuration, Linstor does _not_ fall back to backup\_nic when default goes offline.  
What else needs to be configured? How would I fail over manually? The documentation suggests manually creating paths, but that is not practical with hundreds or thousands of resources.

Thanks in advance.