A little update: I tried following other posts again, but when I apply the solution provided there, I cannot connect to my networks anymore. It worked exactly once for each network (when initially connecting to the SSID after making the changes, I was assigned an IP address of the right subnet by my OPNsense box, so apparently everything was working flawlessly), but when I tried connecting the second time around, it didn't work anymore. I'd simply get an error message as seen in the picture:
Neither rebooting my computer nor the router or disabling and reenabling the respective SSIDs changed that. However, connecting to the OpenWRT AP via LAN works.
I checked the logs on my OPNsense box, and it seems that my laptop is making false DHCPREQUESTs when switching between the networks:
2024-03-13T19:34:12
Informational
dhcpd
DHCPACK on 192.168.103.101 to [MAC-ADDR] (HOSTNAME) via vlan04
2024-03-13T19:34:12
Informational
dhcpd
DHCPREQUEST for 192.168.103.101 (192.168.103.1) from [MAC-ADDR] (HOSTNAME) via vlan04
2024-03-13T19:34:10
Informational
dhcpd
DHCPOFFER on 192.168.103.101 to [MAC-ADDR] (HOSTNAME) via vlan04
2024-03-13T19:34:09
Informational
dhcpd
DHCPDISCOVER from [MAC-ADDR] via vlan04
2024-03-13T19:34:05
Informational
dhcpd
DHCPNAK on 192.168.1.103 to [MAC-ADDR] via vlan04
2024-03-13T19:34:05
Informational
dhcpd
DHCPREQUEST for 192.168.1.103 from [MAC-ADDR] via vlan04: wrong network.
2024-03-13T19:34:03
Informational
dhcpd
DHCPNAK on 192.168.1.103 to [MAC-ADDR] via vlan04
2024-03-13T19:34:03
Informational
dhcpd
DHCPREQUEST for 192.168.1.103 from [MAC-ADDR] via vlan04: wrong network.
2024-03-13T19:33:11
Informational
dhcpd
DHCPACK on 192.168.101.104 to [MAC-ADDR] (HOSTNAME) via vlan02
2024-03-13T19:33:11
Informational
dhcpd
DHCPREQUEST for 192.168.101.104 (192.168.101.1) from [MAC-ADDR] (HOSTNAME) via vlan02
2024-03-13T19:33:08
Informational
dhcpd
DHCPOFFER on 192.168.101.104 to [MAC-ADDR] (HOSTNAME) via vlan02
2024-03-13T19:33:07
Informational
dhcpd
DHCPDISCOVER from [MAC-ADDR] (HOSTNAME) via vlan02
Explanation of the above:
- 192.168.101.0/24 is the subnet for vlan02
- 192.168.103.0/24 is the subnet for vlan04
- 192.168.1.0/24 is the LAN subnet
What exactly is the cause here? I'm not sure why my laptop is trying to retain it's IP address across networks/SSIDs, but I never had any issues when quickly switching between SSIDs before, neither on my networks nor on other ones, so I'm guessing this is an issue with either my OpenWRT or OPNsense configuration. The latter is fairly vanilla (PPPoE, VLANs, DHCP, DNS and that's pretty much it) and the OpenWRT is configured as described in this thread. Does anybody have an idea of where or what to dig into here?