Hello mhirschb,

I just wanted to add something here regarding your title of your question.

You are writting UDP Client and Server in one. From my point of view if I understand correctly you think that Server is receiving your messages and client is replying back.

If this is the case it would be nice to read a similar question What is the difference between udp client and server?.

Answer given by sundialsvc4 from the question:

“The difference between a client and a server” has nothing to do with “UDP.” Rather, it has to do with the role that each program plays, in relation to one another. A “server” is any computer program that is primarily designed to talk to other computer programs, rather than to people. “Servers” often work by listening on network connections ... TCP/IP or UDP ... but some internal-only servers use other techniques such as named pipes. Many commercial servers support multiple modes of communication. Within CPAN, you will find substantial building-blocks for constructing server programs. If you look hard enough before “just diving in,” you’ll find that a great deal of your work has been done for you. The code is, by and large, very high-performance, reliable, and well tested.

I hope this clears things a bit, as NetWallah said start implementing your solution and repost and we will be more than happy to assist you with your solution.