From GL-B1300 LAN, I could access any network above; ISP router LAN and GL-B1300 Guest cannot access GL-B1300 LAN - this is correct behaviour I want.
This was all working correctly until I updated the firmware to 3.105. From the GL-B1300 LAN I can still talk to devices on GL-B1300 Guest, but now I cannot talk to devices on the ISP router LAN.
I configured all this in the Luci firewall zones as originally posted here:
This was just an upgrade. I’ve upgraded the firmware in the middle of last year as well without problem but I’ve only noticed the latest upgrade to 3.105 has caused this.
I’ve tried pinging a device on the ISP router LAN from the GL-B1300 router and it can respond, but devices on the GL-B1300 LAN cannot contact anything on the ISP router LAN.
I’ve just figured this out. It was the internet kill switch.
When the setting is enabled, any traffic from GL-B1300 LAN and Guest cannot traverse back up to the original WAN. I don’t think this works as intended?
It’s a lot of custom config to wipe out and I really didn’t want to start from scratch as my knowledge of OpenWRT is very flaky. I’m just relieved I found it!