Network LAN taken down by 1 connected device

[TJF1960]

Hi all,

So, I have not seen this before and I wondered if anyone else ever has. 24-port D-link gigabit switch with maybe 16 ports connected to wired devices, computers, ISY, misc normal devices. I came home yesterday and the internet was down but not only the internet, I was not able to connect to local devices thru ssh either. I noticed however that wifi internet was working so I figured the modem and router were working. Wont bore you with all the long and laborious details but it turns out the minute I disconnected my rpi4 which serves nodelink and poly to the isy the network returned to normal! Reconnected rpi and network was down again. Rebooted the rpi and it would never boot back up. Installed a new formatted sd card with a 3-month old image and she booted right up and the network has been working since just fine.  Is that not bizzare? Has anyone seen something like this before? 

Question, So, obviously the sd card must be corrupted, but I wasn't as good about making backups in the last couple of months as I normally am. I wonder if I can insert the sd card into a usb card adapter and pop it into the rpi and retrieve some data I would like to have? 

Thank you,

Tim

 

 

[larryllix]

This all sounds very familiar. Many routers could not handle enough devices in the NAT memory space.

In mine the third party firmwares made the problem worse by adding features that ate more NVRAM bytes, but they did identify the problem.

Buying new routers I have found that no router brands will disclose what their capabilities are for that aspect. Many are now stating how many connections they can do on each WiFi band but the totals, including wired, are never disclosed and support people have no idea what you are asking.

The really bad one I had was a ASUS RT-AC92u. After I purchased the memory was doubled in size. grrrrrr....

Sent from my SM-G781W using Tapatalk

[TJF1960]

@larryllix,  I have to admit you lost me. How does a router that can't handle enough devices in the NAT memory space  relate to a corrupt sd card on a rpi4 pulling down the network? Or better put, how does a corrupt card affect a router that can't handle enough devices? 

Thanks,

Tim

edit, I am not asking in a jerk style fashion, although I think it may have come across that way. I am just trying to understand your point of view. I am genuinely interested in understanding.  Thanks!

[larryllix]

3 hours ago, TJF1960 said:

@larryllix,  I have to admit you lost me. How does a router that can't handle enough devices in the NAT memory space  relate to a corrupt sd card on a rpi4 pulling down the network? Or better put, how does a corrupt card affect a router that can't handle enough devices? 

Thanks,

Tim

edit, I am not asking in a jerk style fashion, although I think it may have come across that way. I am just trying to understand your point of view. I am genuinely interested in understanding.  Thanks!

Any bad device on a LAN can pull down your whole network.  In my case a bad router issued bad IP addresses, or forgot them, to my ISY and polisy. Both devices were spewing data to IP 0.0.0.0. This can make the router crash as the NVRAM may have overflowed and crashed it.

In your case this may be possible if the bad RPi went into a massive DoS style, data storm. I have found routers will just shut down when faced with weird stuff like that, to protect the WAN, the LAN or whatever the designer thought was necessary with their built in "virus protection and anti-attack schemes"  to protect other devices.