I recently bought an ASRock Pro B550 PRO4 motherboard to use with my old Ryzen 9 3950X CPU for the unraid server I have. The old system worked flawlessly, but with the new motherboard I cannot access internet or even ping my router from the unraid server.

The weird thing is that I can ping the server (and even connect to it) from my PC.

I have a random SystemRescue laying around, when I plugged it in and booted to it everything worked fine: I could ping the router and also could reach the internet, so it is not a router/hardware issue.

I tried the following already, but none of it fixed/worked:

• Enable/Disable bonding/bridging.

• Change to/from static IP (so tried both DHCP and static)

• Connect a random ethernet USB dongle, same thing, could reach the server, but the server could not reach outside

• Load r8168 driver from https://github.com/jinlife/unraid-r8125-r8152-driver, and disable r8169 driver

• Update unraid to latest version 7.2.2

• Downgrading to unraid 6.12.15

• Safe mode

• Different network cable

• Delete /config from pendrive (factory reset?)

• Various random thing copilot told me to do:

  • Routing table is correct, shows my router IP

  • arping works, ping doesn't

  • ethtool shows 1000Mb/s full duplex, link detected

• Updating kernel to 6.17.0 from https://github.com/thor2002ro/unraid_kernel, unraid works, and I can see the new kernel, but the network is still not good

Please, someone help me out, I'm out of ideas.

Attached diagnostics

blackserver-diagnostics-20251203-0938.zip

Edited December 3, 2025Dec 3 by BlackSun
added some other things I tried to fix the issue

No link is being detected on the onboard NIC; connect a cable to that NIC, remove the USB adapter, and post new diags.

I think that diagnostic was with USB ethernet (so eth1 had the connection), attached a diag where the USB is not connected and the cable is in eth0

blackserver-diagnostics-20251203-1034.zip

Config looks normal, but there's no connectivity, typically a DNS issue, post the output from:

cat /etc/resolv.conf

I don't think it is a DNS issue, because I cannot ping IPs either (not even my router, but arping works on it), I also tried to change DNS from my router to 1.1.1.1 and did not help at all (my router can act as a DNS server).

Result of cat /etc/resolv.conf:

# Generated by dhcpcd from br0.dhcp

nameserver 192.168.1.1

# Generated by rc.inet1

---

I found something interesting:

Time sync seems to be sometimes working sometimes not, right now it says it could sync (i have time.google.com and pool.ntp.org set). Clock is synchronized using 1 NTP servers, time offset is < 1 μs

But for example if I try to download a plugin it says network failure

plugin: installing: community.applications.plg
Executing hook script: pre_plugin_checks
plugin: downloading: community.applications.plg ...
plugin: community.applications.plg download failure: Network failure
Executing hook script: post_plugin_checks

After I changed settings in Date and Time it started showing Clock is unsynchronized with no NTP servers again

Edited December 3, 2025Dec 3 by BlackSun
new observation added

If you get the same issue with both the onboard and USB NICs, it suggests to me an external problem, but to rule out a config issue, create a new flash drive using a stock install, no key needed, then boot with it and retest.

I already created multiple bare new installs, even with different unraid versions, none of it worked, but booting SystemRescue instead (same hardware) everything worked fine.

What I did not try yet is a different pendrive, I'll try it now.

---

Did not help, new pendrive without doing anything to it (other than installing unraid 7.2.2) does not work either.

Edited December 3, 2025Dec 3 by BlackSun
added result

could it be that your router/switch has a setting based on mac addresses in its firewall?

If you have changed hardware this has changed too and no new card would match the old entry...

But then SystemRescue wouldn't work either, it has the same mac (as I used it in the same hardware as unraid).

Also I checked the router settings and I couldn't find any mac filter.

---

I just tried SystemRescue again, and it stopped working (it did work yesterday), what

Edited December 3, 2025Dec 3 by BlackSun

Okay, it seems like it was a router issue, because I disabled static IP for unraid server in WinBox and let it get a random IP and now it works WHICH I'M 100% SURE I DID YESTERDAY, but whatever.

Now it works, thanks for the helps!

---

The previously mentioned indeed fixed the issue, but it was a surface fix. The problem is that my MikroTik router did not update the ARP table (whatever that means) to the new mac.

Executing /ip arp print revealed that 192.168.1.194 had the wrong MAC.

Running /ip arp remove [find address=192.168.1.194] fixed the issue immediately.

Edited December 3, 2025Dec 3 by BlackSun
Extending on the issue a bit, in case someone else has the same issue in the future

The problem is that my MikroTik router did not update the ARP table (whatever that means) to the new mac.

very unlikely!

ARP is cached for 1hr only normally, down to 30s for non-answered requests.

But of course, you can make it go crazy if you change cards faster than these timeouts

The main reason is more likely that you were not cool enough and waited for the correct timeout

(ARP ? address resolution protocol, aka a list which MAC currently represents one specific V4 IP address. For V6 something alike ist called NDP (neighbor discovery protocol). Does the same but works totally different.ARP is based on broadcasts whereas NDP is based on specific ICMPV6 packets to the F800:: address range)

Edited December 3, 2025Dec 3 by MAM59

14 minutes ago, MAM59 said:

very unlikely!

ARP is cached for 1hr only normally, down to 30s for non-answered requests.

But of course, you can make it go crazy if you change cards faster than these timeouts

The main reason is more likely that you were not cool enough and waited for the correct timeout

(ARP ? address resolution protocol, aka a list which MAC currently represents one specific V4 IP address. For V6 something alike ist called NDP (neighbor discovery protocol). Does the same but works totally different.ARP is based on broadcasts whereas NDP is based on specific ICMPV6 packets to the F800:: address range)

The actual "issue" is way simpler, in my infinite wisdom I made the ARP static when I set up the router back when I first created the unraid server and 100% forgot I did that or even remember that it exists.

in my infinite wisdom I made the ARP static

LOOOOOOOOOOOOOOOOOOOL

Yeah Mikrotik Routers are great but not good for the untrained heart. You can do too many stupid settings.

Normally ARP is a self contained and not configurable protocol, no need to twiddle around with it.