Change smb://new-host-4.workgroup to smb://whatiwant.workgroup
Did you try the local hostname setting in Sharing preferences? It's found by clicking the Edit... button in Sharing preferences.



If that doesn't work, check that the DHCP Client ID isn't set. Some DHCP servers will use it to assign a hostname.

You can find it from the Advanced section of Network Preferences, under the TCP/IP section. Make sure that you have the proper network interface you use selected when you click the Advanced button.