I am building an offline homelab network consisting of 3xR605 routers and 1xSG108P switch. Included topology picture. I am testing and verifying connection between the networks. I can successfully ping from network D to the the gateway and PC of Network A. However, I cannot do the reverse, ping from Network A to Netword D or any of its devices. Both networks can ping the opposite routers "outside" facing interface. I have disabled all the standard security features such as block ping from wan and such. I am also doing all the configuration in standalone mode on the routers. The only thing different on network D is the vlan configuration.