Create a TCP/UDP server client performance test

[FreakaZoid2]

I am trying to get a grasp on some performance issues i am seeing with some clients that are running on VM Servers. Previously most of my clients were on physical servers and now they are really pushing VM Servers. Some of the clients experience nominal performance loss but on others i am seeing a 3-7times slower response.
So I am wanting to create/find a TCP server/client example so i can get a performance standard at each site (good or bad). I would also like to look into UDP server/client performance as well.
Anyone have a good starting point.
General test of just pushing large amount of data to/from server/client
maybe a second to to send lots of little amounts of data to/from server/client.

Delphi 10, 10.1

[lexd]

I've been looking for a IPv4 TCP Client/Server pair per computer where one computer is a server to the other computers with my software.
I found windows has features to find computer names or network names but not IP addresses that IPv4 TCP Client/Server relates to better. So Network names are ideal to count the amount of windows computers on a LAN.

[FreakaZoid2]

I have a 3rd party software the uses tcp/ip to transfer data from server to client. currently on a physical server/workstation configuration it is super fast at data transfer. However, VM Servers are starting to overtake the physical servers with my clients. Some of the VMs have decent performance, while others have performance degradation that the software is useless to clients.
examples:
Physical Server takes about 5 minutes to perform a specific process.
VM at site A, takes about 8 minutes to perform the same process.
VM at site B, takes about 9 hours to finish the same process.
My site B client complains to me about how my software is the problem.
I ask 3rd party vendor and they say VM is the problem and nothing they can do about it.
So I am wanting to have something that i can run outside of my application that will show my clients how fast/slow their TCP/IP transfer is.

[lexd]

I'm not anywhere as familia or experienced as you. Everything is built from the basics. I have been thinking but have not tested it yet.
TCP - transfers the data & checks the data is correct as well. That's critical to my needs. I want to move 70% below 100Kb and 30% might reach 16 Mb. But like a FTP servers (Basically TCP), file downloader's divide the file up so if one section of the file is slowed, other parts of the file is still getting moved and delays become less (many threads).
Is this a way to increase transfer speed or some type of compression used with VM servers?

I want to ask you if you have a IPv4 LAN how do you find other IP addresses of the other computers on the LAN?