Case 1: PC A: 192.168.1.2 / 24, and it connects to LAN port1 of router A PC B: 192.168.2.3 / 24, and it connects to LAN port2 of router A Given above we know A and B can't talk to each other due to different subnets
Case 2: PC A: 192.168.1.2 / 24, and it connects to LAN port1 of router A PC B: 192.168.2.3 / 24, and it connects to LAN port1 of router B router A: its WAN port connects to router B's LAN port 2, router B has been configured to route packets for PC A to router A
My question: in case 2, the packet will move in the path PC B -> router B -> router A -> PC A successfully, however I wonder since the packet still has its source IP as 192.168.2.3 and target IP as 192.168.1.2 which are of different subnet, when PC A receives the packet, it will still check the packet's source IP with 255.255.255.0 to get PC B's subnet which will be different from PC A's like how it will in Case 1, which should again prevent the packet from reaching PC A. What has the router done to make the packet successfully reach?
Many thanks!