Help please :) Intermittent network issue

wonko · 10 Aug 2022 at 15:42

It might be a long shot, but what happens if you unplug the network cable from your wife's PC and then turn it on?
I had a faulty monitor power supply many years ago that put out so much noise over the mains that it knocked out the ADSL connection, but only while the power supply was 'warming up' as the monitor came out of standby.

ChrisD. · 10 Aug 2022 at 16:15

iostream said:
Good advice, thank you - I will look at the DCHP reservation range tonight, but I am 99% sure my "static" assigned ones are within the pool of assignable addresses, i.e. something for me to fix.

Had a quick peek over lunch at TCP/IP v4 settings - both IP address and DNS are set to "obtain automatically", so everything is blank.

Definitely check this as Mac flapping on the switches can bring the network down.

iostream · 10 Aug 2022 at 22:18

wonko said:
It might be a long shot, but what happens if you unplug the network cable from your wife's PC and then turn it on?
I had a faulty monitor power supply many years ago that put out so much noise over the mains that it knocked out the ADSL connection, but only while the power supply was 'warming up' as the monitor came out of standby.

Interesting! I worry it will be something wild like this that has cropped up. However sometimes an hour or two can go by after she boots up before the network goes down, so it isn't during boot up.

iostream · 10 Aug 2022 at 22:21

ChrisD. said:
Definitely check this as Mac flapping on the switches can bring the network down.

Alright, DHCP reservation range is now updated to be between 192.168.1.2 and 192.168.1.180.
Both of the reserved IPs are in the 192.168.1.19x range.

Shall report back tomorrow.

Quartz · 10 Aug 2022 at 22:36

Remember to do an IPCONFIG /RELEASE and IPCONFIG /RENEW on both PCs with reservations.

iostream · 10 Aug 2022 at 22:48

Quartz said:
Remember to do an IPCONFIG /RELEASE and IPCONFIG /RENEW on both PCs with reservations.

The two reservations I have are on the Raspberry Pi (so I can remote in and update PiHole etc) and on a Windows 10 NUC that serves as my network storage / Plex server etc.

Before your post I've remoted into each and rebooted them, and I can see from the router admin panel that they have the expected IP addresses.

Does my reboot achieve the same as the IPCONFIG /RELEASE and IPCONFIG /RENEW?

ChrisD. · 10 Aug 2022 at 22:50

iostream said:
Does my reboot achieve the same as the IPCONFIG /RELEASE and IPCONFIG /RENEW?

In short, no. Clients hold on to DHCP reservations until 50% through their lease when they will ask if they can have the same address again. It's best to release it.

Quartz · 10 Aug 2022 at 22:51

iostream said:
Does my reboot achieve the same as the IPCONFIG /RELEASE and IPCONFIG /RENEW?

I'm unfamiliar with Linux but if they've got the correct new IP addresses you should be good to go.

iostream · 16 Aug 2022 at 21:05

Well, all was well for a week, thought it was solved!
Network down again twice tonight. As usual, rebooting the office switch solves it (temporarily anyways).

My Ethernet testing tool has arrived, so I shall test all the cables next.

iostream · 18 Oct 2022 at 09:36

Sorry for the thread necro, but wanted to post in case someone stumbles across this in the future.

I THINK the problem is either my work laptop (Dell XPS 13 9305) or the Dell dock (WD19TB). The laptop is running Windows 11. I noticed that when I put the laptop to sleep after work instead of shutting down, my problems arise. Seems while it is in sleep mode, it's still doing things, I can often hear the fan running etc. I don't think that in itself is a problem, but that's when the network appears to go down.

Anyways my solution has been a smart plug in the wall socket that powers the dock and laptop. I have it scheduled to cut power when my work day finishes. So now it doesn't matter if the laptop is sleeping or shut down, the dock has no power (and therefore isn't sending traffic via Ethernet).

Seems odd, but that's been in place for about 6 weeks now and I've not had a single issue. So in theory, issue resolved.

Caged · 18 Oct 2022 at 10:53

Is your dock firmware up to date?

Dell Dock WD19/WD22 Series Firmware Update Utility | Driver Details | Dell UK

iostream · 18 Oct 2022 at 10:58

Looks like there is one 'payload' that has a new version (see below). Running the update now, thanks for the link.

jaybee · 18 Oct 2022 at 11:25

iostream said:
Sorry for the thread necro, but wanted to post in case someone stumbles across this in the future.

I THINK the problem is either my work laptop (Dell XPS 13 9305) or the Dell dock (WD19TB). The laptop is running Windows 11. I noticed that when I put the laptop to sleep after work instead of shutting down, my problems arise. Seems while it is in sleep mode, it's still doing things, I can often hear the fan running etc. I don't think that in itself is a problem, but that's when the network appears to go down.

Anyways my solution has been a smart plug in the wall socket that powers the dock and laptop. I have it scheduled to cut power when my work day finishes. So now it doesn't matter if the laptop is sleeping or shut down, the dock has no power (and therefore isn't sending traffic via Ethernet).

Seems odd, but that's been in place for about 6 weeks now and I've not had a single issue. So in theory, issue resolved.

Not really fixed though is it?

It's one of two devices and you have to fully turn them off to stop the issue. It's going to eat away at you until you sort it!

So when one of those devices is in standby, it's doing something funky and polluting your network with weird packets possibly. Surely, just eliminate the dock by not using it and then try putting the laptop in standby and see if the issue persists? I thought you said it was your wife's machine anyway or did I miss something?

EDIT: Can you only get ethernet via the dock?

Caged · 18 Oct 2022 at 11:35

There may also be a setting in your laptop BIOS that determines whether the dock passes through the MAC address of your laptop or uses its own, try changing the setting to whatever it isn't set to at the moment.

iostream · 18 Oct 2022 at 13:59

jaybee said:
Not really fixed though is it?
It's one of two devices and you have to fully turn them off to stop the issue. It's going to eat away at you until you sort it!

So when one of those devices is in standby, it's doing something funky and polluting your network with weird packets possibly. Surely, just eliminate the dock by not using it and then try putting the laptop in standby and see if the issue persists? I thought you said it was your wife's machine anyway or did I miss something?

EDIT: Can you only get ethernet via the dock?

Haha true, although I've largely forgotten about it seeing as it's been an error free 6 weeks

But yes, as per your edit I can only get ethernet via the dock, the laptop only has USB C for IO.

Everything is fine until the following combination - laptop is in sleep mode (and powered via dock) and wife's PC is in use. So I guess there is some sort of conflict. It's fine though if the laptop is either on or off, just not sleep. And sometimes an hour or two goes by before the network goes down - I'm guessing it goes down when the laptop comes out of "sleep" to do Windows updates etc.

iostream · 18 Oct 2022 at 14:00

Caged said:
There may also be a setting in your laptop BIOS that determines whether the dock passes through the MAC address of your laptop or uses its own, try changing the setting to whatever it isn't set to at the moment.

Ah interesting, good idea. I shall take a peek at the BIOS, thanks.

iostream · 18 Oct 2022 at 14:39

@Caged - found the setting, it is currently set to pass through the MAC address. Unfortunately 99% of the BIOS settings are greyed out, looks like I need an admin password from my work's IT department.

Caged · 18 Oct 2022 at 15:13

Does the MAC address of your wife's PC match the MAC address on the label on the bottom of the dock?

iostream · 18 Oct 2022 at 15:37

Good question. Ok I've checked MAC on the laptop, dock sticker and wife's machine - none of them match sadly.
Truth be told I'm ok with the scheduled power off switch for the laptop / dock, not only does it save a bit of power throughout the night, I don't need to listen to the fan every now and again when it's supposed to be sleeping. And of course so far, it has 'solved' the problem.

Although I'm happy to keep troubleshooting as suggestions and questions come in