I have a system with a 2 port Intel I225-V 2.5Gb card in it. (Interface igc0 and igc1).
I am currently using igc0 as my WAN interface to my 2.5Gb fiber service and it is working great. I recently got a second ISP and I am trying to connect it to igc1. No matter what I do I cannot get the NIC to even light up.
- I have checked the cable by using it in igc0.
- I have tried several devices and several cables, no luck.
- I know it is not a firmware/driver issue as I am currently using an interface on the same card.
- I have the interface enabled, speed set to 1000 (just to be safe).
It feels like the interface is 'administratively down'. The only other explanation is hardware failure, but I find that a bit hard to believe. I've never had one port on a multi port NIC fail personally.
Any other things I should be looking into?
Quote from: ati on May 20, 2026, 01:50:18 AMAny other things I should be looking into?
What is the ISP2 device you're connecting to (type/model)?
- Add a small switch between igc1 and the ISP modem/router. The ISP modem/routers are sometimes very picky when it comes to auto negotiate speed
- Or try set the interface speed manually to something you know the ISP modem/router supports
- Or configure it as an additinal LAN(2) interface, connect it to a small switch. That should be enough to see if the link comes up
The modem is an Arris TG1682P. However, I have tried connecting my laptop and a switch directly to the port and nothing worked. I know the modem supports 1000Mb, as I connected my laptop directly to it and that is what auto-negotiated.
The interface has a very generic configuration at the moment.
2026-05-20-[WANCable] _ Interfaces _ 15320KnobHill.internal — Mozilla Firefox.jpg
Its completely pointless discussing anything else until you rule out the hardware issue. The most painless way to diagnose is to download any Linux distro that has live environment like Linux Mint or Fedora. Boot into live environment (do not install) and just try both ports on the NIC by plugging known working internet connection in port 1 and then port 2. See if the link is established on both ports and check link speeds in network manager.
Quote from: Nullman on May 20, 2026, 04:21:47 PMIts completely pointless discussing anything else until you rule out the hardware issue. The most painless way to diagnose is to download any Linux distro that has live environment like Linux Mint or Fedora. Boot into live environment (do not install) and just try both ports on the NIC by plugging known working internet connection in port 1 and then port 2. See if the link is established on both ports and check link speeds in network manager.
I was quickly arriving at the same conclusion. I will have to find a time to schedule an outage.