Networking stops

P

Paul Floyd

In the last couple of days I've seen networking stop working. My PC is connected over ethernet to my ISP's fibre modem router and is configures to use DHCP. It's been working ok for about 3 months.

Trying to restart service netif and routing and dhclient igc0 all have no effect.

restarting netif and routing happen very quickly
service restart dhclient igc0 goes quite slowly, taking a couple of minutes to timeout, printing several DHCPREQUEST and
DHCPDISCOVER messages.

According to lspci the ethernet controller is
07:00.0 Ethernet controller: Intel Corporation Ethernet Controller I226-V (rev 06)

Two questions
- any idea how to prevent this from happening?
- and if it does happen, any suggestions for restarting the network? Rebooting is a bit annoying.
 
When it stops, what is the output of ifconfig?
Is your PC directly connected to the ISP equipment?
Anything in system logs about losing DHCP/DHCP lease expiring?
IPV4 or IPV6?

Instead of restarting services, have you tried physically removing the ethernet cable, wait 30 secs, then plug the cable back in? This would only apply if the PC is directly connected to the ISP equipment. If there is a switch that the PC is plugged into and then the upstream of the switch is plugged into ISP equipment, try unplug, wait, plug in that cable.
If a reboot brings it back up, to me that implies something is detecting a pysical link down/link up situation and reassigning address.
 
mer said:
When it stops, what is the output of ifconfig?
Click to expand...

I'll make notes if/when it happens next.

From memory, the output of ifconfig showed the interface but certainly without the inet line.

mer said:
Is your PC directly connected to the ISP equipment?
Click to expand...

No, via a dlink switch next to the fibre modem.

mer said:
Anything in system logs about losing DHCP/DHCP lease expiring?
IPV4 or IPV6?
Click to expand...

I didn't see anything but again I'll make notes next time.

mer said:
Instead of restarting services, have you tried physically removing the ethernet cable, wait 30 secs, then plug the cable back in? This would only apply if the PC is directly connected to the ISP equipment. If there is a switch that the PC is plugged into and then the upstream of the switch is plugged into ISP equipment, try unplug, wait, plug in that cable.
If a reboot brings it back up, to me that implies something is detecting a pysical link down/link up situation and reassigning address.
Click to expand...

Hmm. I don't want to make a habit of ferreting around under my desk, but I'll give it a go.
 
Just a thought... could it be a dodgy cable? Might be worth swapping it with another one! Or try reseating the NIC card. Sometimes it's the really obvious things that get you :)
 
Paul Floyd said:
No, via a dlink switch next to the fibre modem.
Click to expand...
Ahh. In my opinion, switches are inexpensive, so I typically have extras on hand. That would let you swap in a new one wholesale. If there are other things on the downstream side of this switch, do they all show problems when your PC does?
I'm trying to establish "does your ISP thing hand out addresses via DHCP or is there something else that does"
 
Ageed, same with NICs. I always have a couple of pcie intel pro/1000's lying around that I can swap out. They are dirt cheap on ebay and reliable. I'm not so sure about the new intel NICs like the 226. This sounds either like an intermittant hardware fault, or the OP has installed some driver update or other software in the last couple of days that is knocking out the interface. Unless the problem is at the fibre modem!

I should have added "power cycle the switch" to my list of super-obvious things to try.
 
  • Like
Reactions: mer
My thinking is "DHCP from where?" Some ISP devices are combination "router/modem/wireless" so in theory should be handing out DHCP info.
That's fine as long as one understands it; but in that case IPV4 vs IPV6 may also come into play.
blackbird9 you sig line: good old Adventure. Nice
 
Usually a 'normal' (i.e. non-fibre modem) is an ISP provided inegrated combo of modem, router and switch having multiple ethernet connectors. If that's also the case with your ISP fibre modem, then you can easily create a direct connection (with an optionally new cable) from your FreeBSD system to the ISP modem.
 
if the dlink does pppoe then it is a bit more complicated (ie isp device is bridged, dlink pppoe on ext and dhcpd on int)
 
covacat said:
if the dlink does pppoe then it is a bit more complicated (ie isp device is bridged, dlink pppoe on ext and dhcpd on int)
Click to expand...

No it's just a dumb consumer switch. DHCP from the ISP fibre modem (which has 4 ethernet ports and wifi). I'll try swapping cables/ports so that this PC is connected directly to the modem.
 
blackbird9 said:
Ageed, same with NICs. I always have a couple of pcie intel pro/1000's lying around that I can swap out. They are dirt cheap on ebay and reliable. I'm not so sure about the new intel NICs like the 226. This sounds either like an intermittant hardware fault, or the OP has installed some driver update or other software in the last couple of days that is knocking out the interface. Unless the problem is at the fibre modem!
Click to expand...

That's not an option. The motherboard only has 2 PCI slots. One is used by a cheap NVIDIA graphics card and the other is disabled because the motherboard is maxed with M2 cards.
 
Have you talked with your ISP? You can run tcpdump on the port connected to ISP's fiber router to see if there is any traffic in any direction. You can also temporarily assign a static IP address (assuming you know what IP addr range your router gives) to see if you get further. What FreeBSD release are you running? Did this stop working all of a sudden or you made some change (e.g. os update or cable replacement etc.)
 
Are there any other computers available that could be used to help investigate where the fault lies, e.g. your PC, switch, router?
 
You must log in or register to reply here.
Back
Top