I have a basic use case for my Unraid server as a general NAS and as my Plex media server. No VMs etc. I've been using my onboard ethernet connection for years, but finally made the decision to upgrade my network infrastructure to allow a 2.5 GbE connection between my Windows PC and my Unraid server. The existing motherboard on my Unraid server has two 1 GbE ports (only one of which I use), so I've added a TP Link TX201 PCIe NIC to the server, which I understand utilises the Realtek RTL8125 chipset.

From what I've read on other posts I need to set the new card to be eth0 for it to work properly, via Settings -> Interface Rules. I've seen conflicting advice on how to go about installing and configuring the new NIC, so in the end I just physically installed it, then rebooted with the ethernet cable connected to the old port, tried to identify which MAC address is for the new card, then used Settings -> Interface Rules to select it as eth0. However, when I select the new card to be eth0, I get the error 'MAC address mismatch: Rules contain duplicate MAC address assignments'. I tried rebooting again with both the new and old ethernet ports connected, and with only the new port connected. With the ethernet cable connected only to the new port, I can still login to the web GUI, but I still can't change the new NIC to be eth0.

I can't find any information on if I need to re-configure anything else, like the Plex or DuckDNS dockers either. All seems to be working normal now though - Plex works and I can access my files via SMB. Unfortunately, I haven't installed the new 2.5 GbE switch yet, so I can't yet test for higher speeds, but file transfers are still working fine at my previous max speed of around 115 MB/s i.e. ~1 Gbps.

Am I overthinking this/missing something here?? There's so much conflicting information on these forums sometimes, many times I imagine due to improvements to the OS. Any suggestions or clarifications appreciated!

sirpleximus-diagnostics-20251220-1309.zip

4 hours ago, drmit said:

then used Settings -> Interface Rules to select it as eth0

Yeah! that's Step 1 😁

Step 2 & 3 would have been to assign eth1 and eth2 to the other cards.

There should not be a double listed MAC in the menu.

Then it would be complete 😗

Edited December 20, 2025Dec 20 by MAM59

Thanks for the response MAM.

26 minutes ago, MAM59 said:

There should not be a double listed MAC in the menu.

I can't seem to find a way to do that. The confusing bit is that when I navigate to the Interface Rules page there are four interfaces listed: eth0, eth1, eth2 and eth3; eth0 and eth1 have the same MAC address, while eth2 is slightly different, and eth3 is the one I'm pretty sure is the new card (the PCI device name ends with 0x8125, while all the others end in 0x168):

The options in the drop-down menu also contain the duplicate MAC ending in D2:03. Any idea how you would change the above so there's no duplicate MACs?

Edited December 20, 2025Dec 20 by drmit

hmm... strange...

maybe it is best for you to disable the onboard nics in BIOS?

(maybe one of them is not really meant to be used as a general purpose network interface, but for management access only? Or could it be an ISCSI port or something?)

Edited December 20, 2025Dec 20 by MAM59

The motherboard UG has this to say about the two ethernet ports:

- PCIE x1 Gigabit LAN 10/100/1000 Mb/s

- Realtek RTL8111E

- Supports Wake-On-LAN

- Supports LAN Cable Detection

- Supports Energy Efficient Ethernet 802.3az

- Supports Dual LAN with Teaming function

- Supports PXE

It's an ASRock Z68 Professional Gen3 (Fatal1ty) board...my understanding is the two ports are generally intended for link aggregation, i.e. 'dual LAN Teaming function' with a special Windows driver, but they can also be used to connect to separate networks. Back when this board was in a Windows box I could use either ethernet port to connect to my switch/router; I've never had a switch or router that supported link aggregation so never tried to use it that way. It's always been used with only one of the ports connected at a time, and I can confirm they both work independently of one another (I usually just connect the LAN cable to the first port I see on the back; I don't keep track of which one I'm using, if that makes sense).

Ideally I'd rather not shut them both off in the BIOS in case I decide to repurpose this 2.5 GbE nic later down the track, and then can't work out why the onboard ports don't work...

1 minute ago, drmit said:

Ideally I'd rather not shut them both off in the BIOS in case I decide to repurpose this 2.5 GbE nic later down the track, and then can't work out why the onboard ports don't work...

Switching them off wont kill them.

You can reenable them later on at any time again.

Just to see if things clean up and only eth0 is left after turning them off.

( I would become a bit suspicous about the "teaming function". Every NIC can be used for teaming, so why do they meantion it specially? Or is there a direct teamin support in the BIOS? (if yes: TURN IT OFF!))

Edited December 20, 2025Dec 20 by MAM59

I happen to agree with MAM59. I too have the RTL8111E onboard LAN NIC, but with only one RJ45 port. I tested the onboard NIC for three days before deciding to pull my 2.5GbE NIC from my retired Windows server. All I did was boot into the BIOS, I disabled the onboard NIC, shut down the PC, installed the new NIC into the PCIe X1 that was furthest away from the x16 slot and the CPU for a cleaner signal and booted Unraid back up and it just worked as if nothing had ever happened. My transfers to the Unraid server now stay pegged at 285 MB/s or so. Exactly what I was looking for.

After disabling both onboard LAN ports, I was able to reboot and see that the 'Interface Rules' link was gone from the Network Settings page, with only 'Interface eth0', 'Interface eth3', 'Interface Extra' and 'Routing Table' as options. Everything seemed to work OK but eth3 was showing in red as not configured. I couldn't figure out how to reassign the MAC at eth3 to be eth0; eventually I clicked a 'Reset' button on either the eth0 or eth3 page (a bit unsure which) that nuked my connection to the server entirely, after which I couldn't log back in from a browser on my Windows PC. I restarted the server, logged in via GUI mode and noticed 'Interface eth3' was now gone. I now only have 'Interface eth0', 'Interface Extra' and 'Routing Table' as options on the Network Settings page. Bonding and Bridging were now turned on by default in eth0 - those were off in the previous configuration, so I switched them off and all seems to be running well.

So I don't know if it was switching off the 2 onboard LAN ports that allowed me to use that 'Reset' button (don't recall that being there previously?), or if that Reset button was there all along and all I needed to do was click it.

Still can't test for the higher speeds yet, need to wait till my new switch arrives next week. Keen to see if this was all worth it!

I love Unraid but I've gotta say re-configuring anything can be quite the challenge sometimes! You would think installing a new nic would be a bit more straightforward.