ZDoom

I tried to set up a game with my friend. Tried using Zdl using default settings two players on map one.I gave him my pc name. And then he got a error. this is the error. gethostbyname: couldn't find my pc name.
HOST_NOT_FOUND

Please avoid randomly capitalising words in your post, as it makes it rather hard to read.
HOST_NOT_FOUND is a socket manager error, not ZDoom. You can ping the same hostname in the command prompt to double check. Make sure it's correct, and that you are both on the same LAN to be able to use your PC's network name (the Windows network shares will also confirm this).