Problem
After some forum and internet search it seems the primary reason for the Realtek RTL8125B 2.5GB network card not working if for a lack of the right driver in the Truenas Scale. I’m currently on version 25.04 so it still seems a problem. I found the existing ticket NAS-124224 was created suggesting to create a feature request so that it can get voted on.
Impact
I found this topic has been brought up multiple times even with Truenas Core. Common statement is built-in driver packages in Truenas modifications should be avoided. As it would break with every new release of Truenas.
User Story
As mentioned in ticket NAS-124224 maybe offer a GUI option to select varies drivers to different peripherals. 2.5GB network cards are really cheap.
Um, I am using RTL8125B without any issues on multiple TrueNAS boxes. I have no idea what people are talking about when they’re claiming it’s not supported, since I didn’t have to do anything other than pop the card in.
I read that on the forums for some people it just works. In my case the nic is able to link up while the system is still booting through BIOS. Once it gets into Truenas link turns off and does not show up in the GUI. Running some linux commands i’m able to see the hardware but I believe it has a incorrect realtek driver stack attached to it. I’ve read you can manual replace the included driver however it is typically not recommended. This is my personal backup so I’m not willing to risk it messing with system level files.
Nics are so cheap and plentiful these days a 2.5gb Intel card is 25 bucks and an Amazon box away. Especially since Realtek cards are known bad entities for truenas and that’s a short list.
I tried briefly on 25.04.1 and it seemed to work for me for a Realtek-based 5G PCIe device. Can someone please double check and confirm?
I had to revert the machine back to 24.10.2 due to issues with VMs.
I saw a post where a user had two different revisions of the device. One worked fine (rev 05), one didn’t (rev 0c). The one that didn’t was integrated on an Asus motherboard. Seems like an update to the included 8125 driver might fix the issue.
I have the same issue. Doing an ASUS motherboard swap, new board has the 2.5Gb Realtek, and it doesn’t show up. I just use it for management, not storage, but not having it will force me to add another NIC to the box and do some reconfiguration to get working again.
My cheap Realtek 8125BG card just works fine on both 24.10 and 25.04. In fact I tested 2 cards. One from Amazon, and another one from AliExpress. Not sure what exactly the “G” suffix stands for though.
It’s problematic when there are multiple Realtek NICs so a motherboard NIC will force the wrong module. I’d quite happily compile the new driver but TrueNas no longer allows this.
I have realtek RTL8125B networks cards that do not work out of the box on different flavours of linux, I also have RTL8125MG network cards that do work.
I avoid them now, I don’t remember which version but a rtl8125 worked out of the box with proxmox but not proxmox backup server.
I think I just fell into this problem after asking ChatGtp to advice on a 2.5gb card for my combo of MB & Truenas version. The thing doesn’t even show up in the web admin. Any news on when or if this driver is going to be added?
“Welcome to the Wonderful Linux Land of Plenty Drivers!”
(For peace of mind, just stick to the list of server-grade hardware that is approved for FreeBSD.)
