so we want to verify connectivity by pinging between PC1 and PC2

as we can see there is communication between PC1 and PC2

so now we are going to try and ping PC3

yeah as we can see it pinged

so if we want to send a message from PC1 to PC4 and simulate it we can see that it dose not go out of R1

so we find out of this that R1 is not allowing the traffic to go through

lets now go to R1

and we want to see the running config in en mode

using

we can see