Opnsense: Fresh install, no ping and no dns. Hardware issue?

[D1Ck3n]

Hello everyone,
I am completely new to Opnsense and am currently trying to build a network with it at home.
Unfortunately, I have a problem that is driving me crazy!

The scenario: I bought a small mini PC with 2 NICs for testing purposes. Similar to this one:
Everything was going well! I was able to update the system and my VLANs were working great.
Now I tried two different fanless mini PC with 4x 2.5GBit NICs, but unfortunately, almost nothing works there. I freshly installed OPNsense and already during the firmware update I get this message:

***GOT REQUEST TO CHECK FOR UPDATES***
Currently running OPNsense 25.1 (amd64) at Sun Jun 8 00:58:03 CEST 2025
Fetching changelog information, please wait... fetch: https://pkg.opnsense.org/FreeBSD:14:amd64/25.1/sets/changelog.txz: Host does not resolve
Updating OPNsense repository catalogue...
pkg: https://pkg.opnsense.org/FreeBSD:14:amd64/25.1/latest/meta.txz: No address record
repository OPNsense has no meta file, using default settings
pkg: https://pkg.opnsense.org/FreeBSD:14:amd64/25.1/latest/packagesite.pkg: No address record
pkg: https://pkg.opnsense.org/FreeBSD:14:amd64/25.1/latest/packagesite.txz: No address record
Unable to update repository OPNsense
Error updating repositories!
pkg: Repository OPNsense cannot be opened. ‘pkg update’ required
Checking integrity... done (0 conflicting)
Your packages are up to date.
***DONE***

The routers has received an IP from the ISP, but I cannot ping anything or resolve anything via DNS.
Another mini PC with the 2 NICs is running fine.
Could this be due to the hardware?
i tested two mini pcs like this:

for sure i googled a ton and even asked AI but nothing i found worked for me

 

[louie1961]

I know next to nothing about Opnsense, but if it were me I would hook a keyboard and monitor to the device in question and see what information the console/command line can offer. You also may need to re-assign the network interfaces. You can also check the bios with this configuration and ensure the NICs are turned on.

 

[D1Ck3n]

Okay, i think i found my issue: the first NIC (igc0) was not able to communicate in any way with my ISP. All the time i checked the Gateway settings and everything was green. then i checked the settings of my default gateway and there was this option checked:
Disable Gateway Monitoring (shows gateway always as green)
after i unchecked this i saw that the gateway was offline -.-
So, for testing purposes, I assigned the third NIC (igc2) to my WAN and connected it, and lo and behold: my gateway is working again!
I can resolve and ping everything on the internet from the router itself!
I'm still wondering what caused the problem. Does my ISP not like the MAC of the first NIC? Was my ISP's DHCP not working properly? My third NIC also received a new IP from the ISP: 95.xxx.xxx.xxx

 

[TrevorH]

If you connect to your opnsense box over ssh and then `sudo su -` it'll give you the maintenance menu, option 8 off that drops you to a root command shell. From there you can run `ifconfig igc0` and the 'flags' line tells you whether it's up or not. If you run `dmesg | grep igc0` you can see 'link status changed' messages. If you plug a cable into that port and the other end into a working switch port you should see it say the link status changed to up and when you remove it it should say it's down. If you do not see those ten you either have a dodgy cable, a dodgy port on the opnsense side or a dodgy switch port. Also `grep igc0 /var/log/system/system_*` should find mentions in the system log files and those have timestamps which make them more useful.