> I'm assuming LAN traffic still works in this case. Blocking outbound RFC 1918 addresses is a fairly common firewall configuration to prevent any LAN traffic

> I'm assuming LAN traffic still works in this case. Blocking outbound RFC 1918 addresses is a fairly common firewall configuration to prevent any LAN traffic from leaking out into the internet due to weird or misconfigured NAT rules, etc. It doesn't prevent that traffic from traversing the LAN, just if it might try and escape the WAN.