Questions about a Server Emulator

[Siebe15]

Hi,

I want to know how a server emulator works?
So I mean what you must code to make a full working emulator like Fagnet?

Greets.

[ProofPros1]

when you use the emulator fagnet you must nothing code basicly

[Siebe15]

I doesn't mean that. I mean how do you make a Server Emulator? (So I mean what for codes like Database Manager, TCP Client)
My real question is how can I find packets so you can run it on a Server Emulator? You have to get packets that it sends to the Server, right?