[OPEN] DHCP Lease not renewed on 2 of 4 identical devices (custom compile)

[lhurt]

Problem

There are 4 identical Sonoff iFan3 devices for my ceiling fans. They are supported by tasmota. 2 of them don't do a DHCP lease refresh that causes the devices to become unaccessible as the leases time out and DNS can't resolve the ip anymore.
Only a power cycle can trigger the dhcp lease request again and that's pretty unhandy to climb a ladder and power cycle the device (don't want to flick the fuse as my 24/7 server is on it as well).

(Maybe?) Helpful additional Information

• Identical 12.4.0 firmware that I compiled by myself to enable MQTT TLS
• 2 devices work as expected and renew their IP every 5 minutes (set in DHCP server)
• all devices are the same hardware, they were actually bought in one batch
• IP Address is set to 0.0.0.0 on all devices. They request their IP on reboot as expected

Actions tried for resolution

• Updated to a new version. The issue was already present with a previous 12.3.x version
• Reset the device with reset 3 and reset 1 and did powercycle the device after
• Tried official firmware
• Reflashed one of the not working devices from scratch without and also configuration from scratch

Known workarounds

• reboot the device every day via API (that's dirty)
• assign a fixed IP, but I don't want to mess around with IPs. I'm planning to change my base network and this would be nightmare

Any ideas what happens or what I do wrong or what I could do to get dhcp going?
Thanks a lot in advance.

[schrej-zz]

Hi,
I have the same issue now.
I changed the subnet mask of the DHCP server (Fritz!Box) and afterwards the devices had an IP within the open DHCP range despite I assigned a dedicated IP address for them in DHCP.
Even Restart 1 didn't change the IP address to the assigned one.

[s-hadinger]

This is a router issue. Tasmota does not remember IP addresses after a reboot.

[schrej-zz]

Hi,
I can confirm this.
The Fritz!Box lost the fixed assignements to IP an address after subnetmask change.
Thanks