How does the router find out the subnet mask?

Question

Computer networks

Why are masks stored in the routing table? They are not sent along with the package. And how will the router understand where to send the packet if 2 computers with the same ip addresses but different masks are connected to it?

Answer 1

how will the router understand where to send the packet if 2 computers with the same ip addresses but different masks are connected to it?

He won't understand at all. This will not work - your computers will fight at the level of sending the initial packet - the router will constantly update the arp-table and throw out packets that came from "not from there".
Read oilers until enlightenment.

Answer 2

moreover, the routing table is also not transmitted anywhere, neither the address nor the mask :) the mask limits the boundaries of the range of addresses for which a specific gateway from neighboring ones is responsible.
If
2 computers are "connected to the router", then he knows them at the 2nd level, at the level of poppies, and he can correlate ip / mac.
2 computers with different masks and 1 ip .. this is nonsense :) this will not work normally.