One ip address for two interfaces?

Question

Computer networks

Why can't you use one ip address for two interfaces on the same host? Well, for example, for two different interfaces, two different machines cannot have one ip-address. Then you won't be able to tell the cars apart. But why, for example, one router cannot have two interfaces with the same IP address?

Answer 1

When an incoming packet is received and passed to the OS layer, the OSI link layer routing information (including the interface ID) is erased, and the OS structures serving the network and transport layers store only the IP address of the destination (i.e. your machine) .
Accordingly, after the application software generates a response and, using sockets, instructs the OS to send it to where the request came from, the OS will have a dilemma through which of the two interfaces to route it.

Answer 2

This can be done!
For example, according to FreeBSD: we smoke bamboo and read the CARP manual...
Just your case :) - two interfaces, but the address will be the same;) (although two different IP addresses will be involved, to which " binding" one CARP interface...)

Answer 3

you can:
link aggregation. bonding.