Raspberry Pi "crashes", unable to SSH until hard reboot

[NovaKevin]

I run a couple Discord bots on my Raspberry Pi, and every couple days it will "crash". My bots will go down and I'm unable to SSH until I unplug it and plug it back in. I noticed this in the syslog around the time of crash, something about "router expired":
https://pastebin.com/CCWigQhq

It seems to me like maybe my pi is still running but something with the network is not allowing any connections. I could be wrong, I don't know anything about networks. Any suggestions?

[cpc464]

Hi NovaKevin, it looks like the wireless connection (wlan0) is going down, which suggests that your Pi is networked on wireless. Wireless connectivity is convenient but isn't really appropriate for servers, as the speed varies and the connection can become intermittent.. If you are running a service that needs to stay up all the time, I recommend using wired Ethernet instead.

JIm

[skywatch]

I have the same issue with wired rpi 3 model b units (two of them doing it).

[cpc464]

If you are seeing problems from wired Pis then that is a different story. What error messages are produced by the wired Pis? Are they really crashing (and rebooting), or just freezing until you power them off? Or is the sshd service just dying, so you can't log in ? Clues will be found in the log files.

[skywatch]

In my case the pi will run for days or weeks without a problem and then it stops responding to all network traffic.

No response to ping
No response to http
No response to ssh

The pi just sits there until I force a reboot by pulling the power and waiting 30 seconds and reconnecting power. Then it all works again.

Both pi are running headless and so I can't see the logs. I have 2 x pi3 doing this exact same thing.

[cpc464]

Hi skywatch

Regarding your wired Pis, the fact that they run headless should not prevent you from seeing the logs. Have you looked under /var/adm? Logs of interest are kern.log,. syslog and messages. I run a number of Pis in headless mode and regularly check the log files if/when there is a problem.

The sympoms do sound like a system freeze of some sort, assuming you are not running a firewall (whose possible misbehaviour could make a Pi unresponsive), and assuming the problem is on a wired Pi.