I'm going to post this here, in case it helps other people - since all the other threads around this topic that I referenced in troubleshooting this are Locked and can't be updated.
Setup:
Existing connections (at least Pi3 client to Pi4 server) keep the client-server relationship viable, meaning devices with ongoing or regular sessions (e.g., SSH, established TCP connections) somehow continued to have successful connections..
New connections fail—any new client device (Windows, Android) trying to connect to the Pi4 (e.g., SSH, web server) cannot establish a connection.
Initially, the only fix was a reboot.
I later discovered that partial recovery was possible: If an client that cannot access the Pi4 is pinged *from the Pi4* server, after several failed pings, the connection is restored, and new connections from client to server start working again. ARP table, my initial suspect, looked normal when the issue occurred.
Other troubleshooting Attempts (All Failed to Resolve It):
This is the post viewtopic.php?t=361116&sid=1f02945e3cb4 ... &start=100 I followed for that.
It has now been stable for 2 months for all clients.
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More detailed information, should it be relevant:
Setup:
- * Pi 4 Model B - 8GB running headless, kernel 6.1 as server, purchased 2023[/li]
* Wi-Fi only (no Ethernet)
* DHCP (tried static IP as well)
* Wireless Router is within 1 meter of the Pi4
* Network: 5GHz WPA2 wireless (this was a temporary solution until I switch to PoE wired Ethernet where this replaces my Pi3, but that is irrelevant)
* IP Assignment: Static IP for wlan0 set in /etc/dhcpcd.conf (static ip_address, static routers, static domain_name_servers)
Existing connections (at least Pi3 client to Pi4 server) keep the client-server relationship viable, meaning devices with ongoing or regular sessions (e.g., SSH, established TCP connections) somehow continued to have successful connections..
New connections fail—any new client device (Windows, Android) trying to connect to the Pi4 (e.g., SSH, web server) cannot establish a connection.
Initially, the only fix was a reboot.
I later discovered that partial recovery was possible: If an client that cannot access the Pi4 is pinged *from the Pi4* server, after several failed pings, the connection is restored, and new connections from client to server start working again. ARP table, my initial suspect, looked normal when the issue occurred.
Other troubleshooting Attempts (All Failed to Resolve It):
- * Set a static IP instead of DHCP
* Disabled Wi-Fi power-saving features on the Pi4
* Added a cronjob to ping to my clients every minute as workaround... this generally "worked"![:-)]( "Smile")
* Probably other attempts too, this has frustrated me for months
This is the post viewtopic.php?t=361116&sid=1f02945e3cb4 ... &start=100 I followed for that.
It has now been stable for 2 months for all clients.
---
More detailed information, should it be relevant:
Code:
$ systemctl is-active NetworkManagerinactive$ systemctl is-active dhcpcdactiveCode:
System Information------------------Raspberry Pi 4 Model B Rev 1.5PRETTY_NAME="Debian GNU/Linux 11 (bullseye)"NAME="Debian GNU/Linux"VERSION_ID="11"VERSION="11 (bullseye)"Raspberry Pi reference 2023-05-03Generated using pi-gen, https://github.com/RPi-Distro/pi-gen, 7c750947a959fb626a70c09fd17c65815df192ac, stage2Linux pi4 6.1.21-v8+ #1642 SMP PREEMPT Mon Apr 3 17:24:16 BST 2023 aarch64 GNU/LinuxRevision : d03115Serial : 100000007cfe11deModel : Raspberry Pi 4 Model B Rev 1.5Throttled flag : throttled=0x0Camera : supported=0 detected=0, libcamera interfaces=0...EEPROM------BOOTLOADER: up to date CURRENT: Wed 11 Jan 17:40:52 UTC 2023 (1673458852) LATEST: Wed 11 Jan 17:40:52 UTC 2023 (1673458852) RELEASE: default (/lib/firmware/raspberrypi/bootloader/default) Use raspi-config to change the release. VL805_FW: Using bootloader EEPROM VL805: up to date CURRENT: 000138c0 LATEST: 000138c0Statistics: Posted by g3rr!t — Fri Mar 28, 2025 2:09 pm