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Severe stability issues on my local network (lemmy.dbzer0.com)

submitted 2 years ago* (last edited 2 years ago) by [email protected] to c/[email protected]

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Hello Hivemind 🙃

i need some advice here as i am losing my mind.

I have a Fritz!Box6591 and 1Gbit/s internet. Now since yesterday my complete network is extremely unstable. IF i can get any connection, it's as fast as it should be. But connections break down within minutes.

If i let the network "rest" for a couple minutes with barely no activity, i can then access everything perfectly fine for a few minutes until everything breaks down again.

What i did:

-Deactivated my local DNS (AdGuard) on my router -Restarted (even with 15 min. of no power) EVERYTHING. Literally everything in my homenetwork.

Since it's not only the internet connection and not one specific device and not even one specific type of connection (two WiFi Devices can't properly connect between each other just as two different LAN Devices on either different Ports on the router or same router port on a switch) i don't really know what to do anymore.

Obviously my router is the only common denominator but i can't see any issues with it. It's not overheating, it's RAM & CPU usage is perfectly fine, it's not gone it powersaving mode, it doesn't throw me any errors.

I already did tracepath's to every device and there is no unexpected hop on some theoretical phantom device (if my DNS became buggy or something).

If i ping one of my servers from my PC. It says i have a latency of 1~3ms but it is obviously hanging really hard. It could have a delay of 15 seconds before the next line in ping appears but that will still claim it had a 2ms latency.

I don't know what to do anymore and where to begin. Any ideas?

EDIT: Here is quick sketch of my network

EDIT2: Found the culprit - https://lemmy.dbzer0.com/comment/324192

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[–] [email protected] 5 points 2 years ago

Alright - i found the culprit.

My Sonos speaker on switch 1 was kinda DDoS'ing me... apparently thats a know issue aswell. It flooded my network with requests and probably looped back on itself.

Well, now they are offline, my network is functional and as soon as i have time i will see what i can do about them. Probably factory reset.

[–] [email protected] 3 points 2 years ago (1 children)

I would try to do it systematically. At my dad's we had a similar problem but not the same and there it was that my dad by accident created a loop in one of the switches.

I would start with turning off the wifi and disconnecting everything from the Fritzbox. Then I would connect a laptop with a ethernet cable to the fritzbox and check if this part works or if the Fritzbox is already broken.

[–] [email protected] 1 points 2 years ago (1 children)

I was hoping someone would come up with some form of magic and found the one thing i forgot...i tried to not disconnect everything (updated my post so you can see a sketch of my network) it would be a looooot of work....but i guess there is no choice

[–] [email protected] 1 points 2 years ago

Without a managed switch, it's basically your only option.

[–] [email protected] 3 points 2 years ago (1 children)

Connect one device at a time and see if you can narrow it down.

[–] [email protected] 0 points 2 years ago (1 children)

i edited my post and added a sketch of my network.

What order would you pick when connecting them again?

[–] [email protected] 2 points 2 years ago

The least complex (in terms of secondary switches) first obviously. But I don't have any specific insights what could be causing it from looking at the diagram.

[–] [email protected] 1 points 2 years ago (1 children)

You may have tried it already but have you tried resetting the Fritz!Box 6591 modem?

[–] [email protected] 2 points 2 years ago (1 children)

no i didn't try resetting it to factory settings.

i set up pretty much stuff in there (VPNs, dedicated IPs, remote access, Phone Service, etc.) and i will delay that until the bitter end.

[–] [email protected] 1 points 2 years ago (1 children)

Ah sorry "resetting" may not be the appropriate way to say it...

What I wanna ask is if you have tried rebooting your Fritz!Box.

[–] [email protected] 1 points 2 years ago (1 children)

oh yeah 😄

I rebooted it multiple times, and took off the power for 15 min aswell to empty the RAM.

[–] [email protected] 1 points 2 years ago* (last edited 2 years ago) (1 children)

Okay. Can you get a stable connection if you disconnect everything and just connect one device (say a PC) to the modem-router?

If it still does not work this way, I suspect your network provider may be having issues.

[–] [email protected] 1 points 2 years ago (1 children)

Disconnecting everything is on my To-Do as others have advised aswell. Issue here is, if you look at the diagram in my OP, you'll see i have a fckton of devices connected and this will take a lot of work to do. I'll do this after work.
My network provider simply cannot be the root of the issue because as i have clearly stated, i have issues connecting locally to my devices. If i ping PC to my Plexserver that's sitting my living room, i get issues, my network provider has nothing to do with that.

[–] [email protected] 1 points 2 years ago (1 children)

Alright I assumed you have issues with outbound traffic as well. Now we are clear that the issues are local only.

lemmy.world has not propagated the edit but I have checked the diagram. Which device is your DHCP server in the network? Also do you have VLANs set up in your network?

[–] [email protected] 1 points 2 years ago

Well technically i have outbound issues aswell, but only do to my network not functioning properly on a local level.

WiFi devices directly accessing the router and doing a speedtest show no issues.

DHCP: Is the router No VLANs

Btw i now disconnected Switch 1, where actually no traffic should go through (doesn't show that on tracepath aswell), an now my network stabilized afaik. On that switch there is my plex server and my Sonos speaker. That's it.

I have to investigate more.

[–] beaumains 1 points 2 years ago

Yo, I have also been having problems with a fritzbox 7490. I initially thought it was the cat6e in the walls but we're having wifi issues as well. Perhaps the devices they built are starting to fail? Flash getting old, capacitors getting swollen etc. I'm hanging out for a microtik replacement just needs approval from the minister of finance.

[–] [email protected] 1 points 2 years ago

My guess was gonna be a broadcast storm caused by a loop. Like a device that's connected to 2 different ports. That or a rogue dhcp.
Either way, taking a capture in Wireshark would have helped.

If these are managed switches, configuring bpdu guard on LAN ports (not on trunk ports to other switches!) would prevent a device from forming a loop.

[–] [email protected] 1 points 2 years ago (1 children)

Are you also using Powerline? This can cause all kinds of wanky issues.

[–] [email protected] 1 points 2 years ago

no i am not.

And even if, two devices connected via WiFi on the Router (directly, not via mesh or access point) shouldn't be disturbed by some wonky powerline should they?

[–] [email protected] 1 points 2 years ago (1 children)

What's the uptime of your router? Is it or any subsystem crashing frequently under load?

[–] [email protected] 1 points 2 years ago

The uptime now is basically a couple minutes as i just restarted it again-

There is no load on my systems at the moment.

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