[SOLVED] Random LAN connectivity issues since 20.7.4

[MartB]

SOLVED
My ubiquiti APS arp spoofed the gateway because of a broken proxy arp implementation.
This had nothing to do with opnsense, sorry for the noise!


Original report below:
Hello there,

i have been using 20.7.3 with the updated realtek drivers for some months and it never gave me any issues.
After upgrading to 20.7.4 my firewall/gateway is starting to not process packets from time to time.
The following symptoms appear when this happens:

- My 4 unifi aps cant "inform" the controller hosted on the firewall box.
- Some windows clients are able to get an DHCP Address but replies to DNS / ICMP pings dont work and i dont have any sort of internet connection.
- The firewall webinterface cant be accessed from the devices exhibiting these symptoms.

This randomly fixes itself after some time.
On windows i found the following hotfix: ipconfig /release & ipconfig /renew seems to somehow make traffic flow again.

I can verify that there are no faults logged inside opnsense, a traffic capture on the firewall system does *not* show the ICMP packets that are supposedly being sent by my clients when i test.

When i ping an affected device from opnsense, i can see the packet reach my client (traffic capture) but of course the reply from the client wont reach the firewall.

Im kinda lost here, this all started after the 20.7.4 upgrade.
Is there any way to rollback without setting up the entire device again?

Edit: I also get Loopback adapter Default Deny messages in my firewall, is this normal?

Edit2:
I attached an image of a ping test that ran from all 4 APs at the same time (slightly different start times).

As you can see the ping recovers after some time.

Kind regards & help appreciated,
MartB

[MartB]

This is slowly driving me insane, it happens randomly all over the place.
Is there any way the firewall is acting up here or is my network driver broken after the netmap changes that were made in 20.7.4?

Im going to switch back to 20.7.3 and see what happens this afternoon, this is a gigantic bummer.