I have two networks, one 192.168.2.0/24 (network 1) with a pfSense Gateway 192.168.2.10 and on another site I have 192.168.3.0/24 (network 2) with a Linux Gateway 192.168.3.10.
These two gateways establish an IPSec-type VPN, where any host can PING or access services on any other host on the other network.
There is no firewall filtering ports for these networks on any of the gateways.
In network 2, I use a TP-Link TL-WR840N v4 with OpenWRT 18.06.5 r7897-9d401013f, 4.14.151 Kernel with LuCI openwrt-18.06 branch (git-19.309.48729-bc17ef6) to provide WiFi access for users.
The settings are the factory defaults in OpenWRT.
OpenWRT can ping hosts on both network 2 and network 1.
Both network 1 and network 2 devices can ping OpenWRT.
The problem is that being on network 1 on any computer I can't access LuCI (port 80) which is on network 2, but I can access the same device via SSH (port 22) normally. When I try to access LuCI, it presents the link with the text "LuCI - Lua Configuration Interface", but does not enter the page to login. Even when I click on the link, the browser is running and not entering the page.
But if I have the same computer on network 2, then I can log into LuCI normally.
How do I access LuCI on network 2 directly while I am on a computer on network 1 ?