Problems with LAN control when firewall is active

[whoifnot]

Hi there,

I own a STY02YM and have been using the Viomi integration for a while now with success.

Recently I configured my firewall to block all wan connections from my STY02YM to the internet. This protects my network from any rogue use of my device. This firewall rule will work fine and block the traffic, but after a few days (5-7) without internet, the STY02YM integration stops being able to control the vacuum.

Rebooting HASS, the STY02YM or my router does not change the behaviour.

Once I remove the firewall rule and activate it again immediately, I regain control of the vacuum from HASS.

I suppose it is some firmware limitation from Xiaomi/Viomi.

Does anyone have experience with this issue?

Warm regards.