Sometimes VMware Fusion 7 (and possibly other versions) decide to grey out network adapter settings for all VMs and/or NAT stops working. This appears to be an oddity VMware just won't fix.
To fix NAT
Go to /Library/Preferences/VMware Fusion/vmnet8 and check whether VMware Fusion has decided to delete or rename your NAT configuration file. For some reason Fusion does that occassionally.
Check whether Fusion has decided to give your Windows machine a different IP address for no particular reason after everything worked for months.
When you modify the nat.conf file to fix the NAT configuration, Use
to restart VMware Fusion's networking subsystem.
- vmnet-cli --stop stops networking
- vmnet-cli --start starts networking
- vmnet-cli --status shows the status
- vmnet-cli --configure resets networking to the factory defaults (and destroys your NAT configuration)
Run these commands while Fusion is running, otherwise they won't work.
To fix greyed out network adapter settings
If Fusion has decided to grey out network settings, quit Fusion, run sudo killall vmnet-bridge, and start Fusion again. Yes, this will totally terminate whatever you have been working on in the VMs. I don't know if it plays well with suspended VMs.
Do not under any circumstances configure NAT for ports 137 (NetBIOS Name Service) and 138 (NetBIOS Datagram Service). It just won't do you any good.