How to distinguish a router from a computer?

Question

Computer networks

Good morning!
A somewhat hypothetical question arose.
There is a network. Local. There are multiple devices on the network. Some of them are computers. Some routers.
Is it possible somehow, knowing only the IP address, to understand what kind of device is hiding behind this address?
(My ultimate goal is to complete the picture of the world that exists in my head).

Answer 1

Find out the MAC by ip Find
out the manufacturer by MAC (there are tables and standards).
Formally, from the point of view of the network, a router is no different from a computer. (Any computer can be a router)
Further, tools such as NMAP can learn the device type based on heuristic algorithms.

Answer 2

In general, no way. If I put two network networks on Windows Server and start transmitting traffic between them - am I a router or not? Or am I still a server? :)
What can you find out.
- device manufacturer. You can almost always find out by getting the MAC of the device and comparing it with the table of MAC address blocks posted on the tyrnet
- Running services. You can almost always find out if it is on the same network as the device and it does not block traffic. nmap or other port scanners
- Device identification. You can find out if services are raised on it that allow manual command entry - ftp, telnet, smtp, imap, etc. When connected to a service port, the daemon serving it usually issues an identification string, often containing information about what kind of device it is
- Number of network interfaces and their settings. You can almost always find out if you have admin rights or if they don’t, but SNMP is installed and running with default settings.
Well, then pure empiricism begins. A computer can have a dozen network cards, but not be a router, or it can have two and be. And it can also be a host carrying several VMs that communicate with each other via an internal switch - will it be a router or not?