Re: Strange network activity connection drops

theKenofKens · ‎15-02-2023

Hoping someone can shine some light here.

I am finding frequent network drops on my home network. Most of it is via a wired Hp switch connected to my BT homehub which connects to FTTP. My wired pc and wifi connected laptops are both suffe

I have setup a ping -t to my 192.168.1.254 and a few other internal devices, all around the same time i see request timeouts.

I thought i would check the homehub logs and see alot of disconnects here? Ive never heard of a Switch failing is this potentially a symptom showing below?

21:59:36, 15 Feb.ARP [del] br0 192.168.1.215 86:ae:96:e9:7d:51
21:59:17, 15 Feb.ARP [add] br0(eth2) 192.168.1.82 10:63:c8:65:86:3d
21:59:10, 15 Feb.DHCP device Disconnected: 192.168.1.20, b4:fb:e4:90:11:e7, Campsitegate
21:59:10, 15 Feb.LAN [DEL] ARP 192.168.1.20 with b4:fb:e4:90:11:e7 from br0
21:59:08, 15 Feb.ARP [del] br0 192.168.1.20 b4:fb:e4:90:11:e7
21:58:57, 15 Feb.ARP [add] br0(wl1) 192.168.1.215 86:ae:96:e9:7d:51
21:58:56, 15 Feb.ARP [del] br0 192.168.1.215 86:ae:96:e9:7d:51
21:58:43, 15 Feb.DHCP device Disconnected: 192.168.1.78, 78:8a:20:70:8c:63, campsite
21:58:43, 15 Feb.LAN [DEL] ARP 192.168.1.78 with 78:8a:20:70:8c:63 from br0
21:58:41, 15 Feb.ARP [del] br0 192.168.1.78 78:8a:20:70:8c:63
21:58:41, 15 Feb.DHCP device Connected: 192.168.1.109, b4:b2:91:d9:40:00, LGwebOSTV
21:58:40, 15 Feb.LAN [ADD] ARP 192.168.1.109 with b4:b2:91:d9:40:00 from br0(eth0)
21:58:40, 15 Feb.ARP [add] br0(eth0) 192.168.1.109 b4:b2:91:d9:40:00
21:58:39, 15 Feb.DHCP device Disconnected: 192.168.1.109, b4:b2:91:d9:40:00, LGwebOSTV
21:58:38, 15 Feb.LAN [DEL] ARP 192.168.1.109 with b4:b2:91:d9:40:00 from br0
21:58:36, 15 Feb.ARP [del] br0 192.168.1.109 b4:b2:91:d9:40:00
21:58:33, 15 Feb.ARP [add] br0(eth0) 192.168.1.91 80:2a:a8:c9:0a:a2
21:58:33, 15 Feb.ARP [del] br0 192.168.1.91 80:2a:a8:c9:0a:a2
21:58:33, 15 Feb.ARP [add] br0(eth2) 192.168.1.157 18:e8:29:c0:5e:52
21:58:27, 15 Feb.DHCP device Connected: 192.168.1.137, f0:57:a6:ef:99:b2, Kenovo
21:58:27, 15 Feb.LAN [ADD] ARP 192.168.1.137 with f0:57:a6:ef:99:b2 from br0(eth2)
21:58:26, 15 Feb.ARP [add] br0(eth2) 192.168.1.137 f0:57:a6:ef:99:b2
21:58:16, 15 Feb.ARP [add] br0(wl1) 192.168.1.215 86:ae:96:e9:7d:51

countrypaul · ‎15-02-2023

I would start by changing the simple things such as the cable between router and switch checking that the contacts are clean before inserting the new cable. Use a mobile phone to take a picture of the socket and make sure there is nothing in the photo that should not be there.

Do you have anything directly connected to the router if so does that show the same symptoms? if you don't have anything directly connected try connecting one of the items that shows the problem and see if it persists.

I have seen similar problems with a bad ethernet card in a PC giving lots of network noise that prevented proper ethernet frames being sent/received but that is much less likely nowadays but worth bearing in mind.

You don't say which HP switch you have, but power supply problems are notorious for being difficult to trace, if the switch has an easily changed power supply it might be worth borrowing (or even buying) one to eliminate the power supply before condemning the actual switch - they do go wrong but not very frequently.

theKenofKens · ‎15-02-2023

HI CountryPaul thanks so much for your thoughts. Indeed i shall try your suggestions tomorrow. I do have a brand new spare Switch so may try swapping that out tomorrow. Also will first try running my office PC direct to the BT router as you say, will report back here my findinds. Ineresting you comment about the PC card causing excess noise, how would you discover such an issue?

countrypaul · ‎16-02-2023

It was an intermittent problem, but we noticed 2 things, one when the problem was present all the lights on a hub (multiport repeater) were flashing so we suspected a fault somewhere, and 2 it only appeared when a specific PC was turned on - so probably a significant amount of luck, as the PC was turned off at night and the user took a day off!

If you have a spare switch then it would make sense to try it and eliminate your current switch as the source of the problem. I would start with the simplest setup Router and office PC only, trying with multiple cables and multiple ports on the router, if the problem is still present, then replace the PC to eliminate it and isolate it down to the ONT/Router. If it is the ONT /Router you can link your office PC to the router and setup a direct link to the ONT to identify whether it is the router of the ONT/fttp supply.

theKenofKens · ‎16-02-2023

OK i think i might have found the issue in the end. I swapped out my main 20port switch which i thought would resolve it but, 5mins later drops in my pings to local and remote hosts were occurring again. I noticed one connection light off on the switch, traced this back to a POE cable to one of my mesh routers currently disconnected since our new extension. The end of the cable was a mess off wires potentially touching eachother!

Im hoping now ive left this unplugged it was the cause of my troubles.

countrypaul · ‎16-02-2023

Faulty cables can throw up weird problems some that you can never make sense of.

Did you run any other tests or was swapping the switch your first step?

theKenofKens · ‎17-02-2023

First step was switch second was the realisation a light was out on one of the connectors and then i realised what the issue could be. Apart from Ping -t that was my only line of interrigation that i could use, i guess fluke or some other hardware level network monitor tool would have told me more.

That's a new one on me i never realised a faulty cable could affect the connectivity of my whole network causing connection issues with many of the interfaces, i thought a switch protected things more like this over a hub! Anyway live and learn, thankyou @countrypaul for your time and thoughts here.