Do you have a spare monitor, keyboard and does your nas have a gpu?
If yes you can connect the monitor and keyboard to your nas and use the menu options that get displayed to reconfigure your network settings.
Not during the boot sequence, after truenas is fully booted.
It will show a menu with options 1-10 (i believe) and option 1 or 2 is to reconfigure your network adapter.
During the boot sequence really doesn’t matter (unless there’s a problem with it, which we don’t have any reason to believe at this point). Once the system boots, it gives you a console menu that you can use to reconfigure the network settings.
I was doing a complex action trying to replace my netwerk card with a better one. So I placed both in the system and tried to migrate settings from one card to the other one, which is drama especially give the fact that you can not have the same defs on both cards and the stupid thing only has one gate way, so I tried to setup IPV6 as second gateway …
Use the console options. It will present 9 options with the first 3 dealing with networks with the main ones 1 and 2. There the networking issue can likely be fixed. Option 5 I think will reset the Truenas configuration file to defaults. Kind of a nuclear option I think.
No other option with the knowledge I had at that moment. Perhaps there was … not sure. I tried a lot before going to defaults.
So, back to defaults and noticed that the system got a IP address of one of the vlans in the network trunk. Using that vlan I could use the default login and upload the backup config to the NAS.
For more info about this read my just written thread related to jumbo frames.