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I have a RPI Zero WH. It's headless. I have SSH and WPA-CONF files.
I recently did a showdown -P to turn the pi off. I moved the pi to a different part of the house. When it powered up, it was unreachable via SSH. The router failed to show that the pi in the dhcp client list. This has happened before, but not every time. I unplugged the running pi and plugged it back in. This time, the pi showed up on the lan with the same IP it had before.

Are there any logs on the Pi that I can look at to see what kinds of failures the pi was getting when it was powering up and trying to join the lan?

TIA

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  • Are you running the latest Raspbian Buster, fully updated?
    – CoderMike
    Commented Feb 27, 2020 at 18:33
  • release was installed mid-Feb and upgraded. Buster - lite
    – MACE
    Commented Feb 27, 2020 at 18:34
  • there's all sorts of logs in /var/log
    – Jaromanda X
    Commented Feb 27, 2020 at 22:18

1 Answer 1

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I'll guess you have a network issue, not a Pi issue. There are a few things you could look at:

  1. Does the new location have a good WiFi signal?

  2. Is there more than one WiFi access point (AP) in your house, and is the one in the new location a different AP?

  3. Do(es) your WiFi AP(s) provide a DHCP server, or do they pass that job through to another router?

  4. Do other WiFi users in that same area also have issues?

If you don't discover any issues with your home network, then you may want to enlist dhcpcd to help. It has many options that could possibly be of use in troubleshooting. Before doing this, you should read the documentation. IMHO, the best documentation is this page at archlinux, and man dhcpcd.

Finally, to answer your question, dhcpcd logs to /var/log/syslog on RPi by default. Take a look at it; if your issue persists after all of the above, please edit & update your question with what you learn & we will proceed from there.

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  • Thanks, Seamus. 1) There should be a good signal. It's w/in 25 feet. 2) It's the only AP. 3) It is the dhcp server. 4) None of the other devices in the house, including three other Pi's exhibited any obvious symptoms.
    – MACE
    Commented Feb 29, 2020 at 3:49
  • Seamus, I checked the syslog on my 4 Pi's and see dhcpcd entries. I now have a baseline of what the log should have and I'll be able to compare that to the log if this kind of things happens again. Thanks.
    – MACE
    Commented Feb 29, 2020 at 4:10
  • @MACE: Keep us posted. One other thing to mention: I'm not familiar w/ the Pi Zero WH, but I believe it has both Bluetooth LE and WiFi built in. I have read that the Bluetooth and WiFi use the same antenna. And so if you're using Bluetooth on your Pi Zero WH concurrent with WiFi this could be an issue.
    – Seamus
    Commented Feb 29, 2020 at 6:58
  • It continues to happen. I'm looking thru syslog. It's big-ish and I don't know what I'm looking for. I'm hoping to use the ocular trauma method -- keep staring at it until it hits me right between the eyes. Based on timestamps, it seems as if dhcpcd isn't launching and that's why the device doesn't show up on the LAN. On one occasion, after I did gain access a "cat /var/log/syslog | grep dhcpcd" command produced an "Invalid instruction" error while "cat adaio.log | grep huff" did not. Yes, the Zero WH has bluetooth. I've done nothing to enable it.
    – MACE
    Commented Mar 2, 2020 at 14:19
  • @MACE: If I understand correctly, your RPi Zero WH is the only one of several devices (incl. 3 other RPi systems) that are having problems. That strongly suggests, contrary to my answer, that the RPi Zero WH is the issue. The statement in your OP that, "I moved the pi to a different part of the house" suggested to me that the environment in that part of the house was different, but seems I jumped to a conclusion. At any rate, I feel there are 2 options for sorting this: 1) re-flash the SD card in your "Zero" & try again, or 2) start troubleshooting the DHCP process. Your thoughts?
    – Seamus
    Commented Mar 2, 2020 at 22:45

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