No, it doesn't have to be set to anything particular. However, it makes sense to choose a DNS domain name that would uniquely identify a user account (username@domain) just like an e-mail address does.
Actually, NFSv4 will default to your DNS domain if not otherwise specified, and machines in a different DNS domain won't be able to mount the share. In that sense, the use of the word domain does make some sense.
No, it doesn't have to be set to anything particular. However, it makes sense to choose a DNS domain name that would uniquely identify a user account (username@domain) just like an e-mail address does.
Actually, NFSv4 will default to your DNS domain if not otherwise specified, and machines in a different DNS domain won't be able to mount the share. In that sense, the use of the word domain does make some sense.