How to deploy a "local server" on Linux?

Question

linux

Hello everyone, I needed to deploy a server for term paper. It is required to do something like: client - server - client, where the server will act as a mail server, in which you can see what requests and "letters" have been received.
That is, in this case, the server is an intermediary in the network, in which you can track messages (having access to it).
Advise with the help of what it would be possible to deploy a server on Linux for this task and what tools are needed in addition to the server itself?
I would also like to understand if it is possible to intercept a message if there is another client in the network (1 server and 3 clients (PCs))?
By the way, I plan to do everything live. Thanks everyone for the reply!

Answer 1

Che I did not understand ... You want to make a proxy?
yes, any modern debian distro or ubuntu will do

Answer 2

Install Vmware or another viriualization server and raise as many machines as you need on it with wireshark, nmap, tcpdump, etc. You will receive a network fragment for experiments.