Use the M.2 A+E slot with an Ethernet adapter.
There’s now a huge variety of 1 GbE single port adapters, both Realtek and Intel chipsets and lots of 2.5 GbE Realtek adapters.
The holy grail for your purposes are 1 GbE dual port adapters, and these are almost available - there are a fair amount of the B+M key dual port adapters, and there are A+E to B+M converters, but it’s a kludge.
I already gave up, sold my board a month or two ago, and bought a Minisforum Venus series PC. I’m using proxmox to host my OPNsense VM and a Windows VM specifically for Nord meshnet. If only this surge of new cards was a few months earlier.
Ive been running proxmox on my 11th gen board with a realtek adapter for 6 months now without any issues. Opnsense is running on it and I have the virtual nics attached to the vm using virtio. The physical NIC is trunking all my vlans to a ubiquiti switch that breaks them out to lan/wan/etc (router on a stick).
In my experience as long as opnsense/pfsense is using a virtual nic using a realtek nic on the host works great.
If it’s gigabit, yes. if it’s 100mbit, then no it’s not safe to assume that at all. Autosensing is part of the gigabit spec, it was optional for 100mbit and not always implemented.
Anybody know where I can buy this? Can’t really find anything
edit:
I ordered this, hopefully it’ll work:
I’m using my old 11th gen board as a proxmox host and the realtek based usb nic is very unreliable.
I improved the reliability of my realtek hardware significantly by using ethtool to turn off scatter-gather and tx/rx offloading. If anyone else is struggling with realtek stability, try turning at least those off, possibly other options as well.
I have my opnsense running under proxmox as one of many VMS, one problem im having is losing access to proxmox via my browser after i connect to the router for WAN
The M.2 NIC does not seem to be recognized at all 
Just tried turning these settings off and instantly lost connection lol
That’s weird. What commands did you use?
My script looks like:
ethtool -K eth0 tx off rx off
ethtool -K eth0 scatter-gather off
ethtool -K eth1 tx off rx off
ethtool -K eth1 scatter-gather off
Exactly what you posted in even the same order.
root@frink:~# ethtool -K enxf44dad0064e3 rx off tx off
Actual changes:
tx-checksum-ipv4: off
tx-checksum-ipv6: off
tx-tcp-segmentation: off [not requested]
tx-tcp6-segmentation: off [not requested]
rx-checksum: off
root@frink:~# ethtool -K enxf44dad0064e3 scatter-gather off
Actual changes:
tx-scatter-gather: off
tx-scatter-gather-fraglist: off
tx-generic-segmentation: off [not requested]
This is the problematic USB NIC:
I’ve tried two realtek based USB nics with the same experience of losing the connection after a while.
The network connection can’t even be restored if I unplug and replug the usb nic.
I just noticed these messages:
Can’t really find anything helpful about it.
But I found this, and I’m trying it out now. Hopefully it’ll be more stable. edit: Nope, just lost connection a couple hours after rebooting…
@Fraoch Do you know any commell distributors that sell to private customers in europe?
No, I have never seen these for sale anywhere.
1 GbE Intel M.2 A+E NICs are common on Amazon from multiple Chinese OEMs. 2.5 GbE Intel I225-V M.2 A+E NICs are quite rare and just started appearing. 2.5 GbE Realtek 8125 M.2 A+E NICs are not quite as rare but still hard to find.
Unfortunately M.2 B+M NICs are taking over, especially for 2.5 GbE. There are B+M to A+E M.2 adapters but then you lose the storage slot while the communication slot sits unused.
I’m familiar with Amazon Canada. One of many Intel I210 M.2 A+E NICs: https://www.amazon.ca/Gigabit-Ethernet-Server-Adapter-I210AT/dp/B0BFFRXFXH/ - this one is the lowest cost, but they all appear to be the same.
One of two Realtek RTL8125B M.2 A+E NICs: https://www.amazon.ca/2-5Gbps-Adapter-2500Mbps-RTL8125B-Profile/dp/B0CLGCC2TV/, the other https://www.amazon.ca/Ducahye-Ethernet-Adapter-Multi-Gigabit-Network/dp/B0C8HBL2DZ/
Could not find any Intel I225V M.2 A+E 2.5 GbE NICs this morning, I only found one B+M. I have seen them before from time to time.
Since these all come direct from China, you might as well eliminate the middle man and look on AliExpress.
The first one you linked looks exactly like the one I couldn’t get to work (that I got from Amazon Germany).
I’ve ordered another one and also an apple thunderbird 2 to 3 adapter to try a leftover apple thunderbird 2 NIC.
So I got the Apple Thunderbolt 2 NIC connected, let’s see if this will be stable.
Apple Thunderbolt 3 > 2 Adapter connected to the old Apple Thunderbolt 2 NIC (Broadcom BCM57762)
It shows up in lspci as Ethernet controller: Broadcom Inc. and subsidiaries NetXtreme BCM57762 Gigabit Ethernet PCIe, so it shouldn’t have USB issues.
Fingers crossed!
Could always just stick a pcie nic in an egpu enclosure if you want to go further down that route.
I’ve already spent 150 bucks trying out various networking options lol
Before I do that, I will just go back to hosting my smart home stuff on an Intel NUC or AMD equivalent.
I just needed a quick solution, because I already gave away my old NUC to a friend and my lights constantly stopped working, due to the network failures
Two days later the solution with the Apple Thunderbolt 2 NIC seems to work perfectly!
