We have two kinds of identification numbers in Norway: national identity numbers and D numbers. Some public and private companies require a Norwegian identification number to access their services. With an identification number, you can, for example, open a bank account, get a general practitioner (fastlege) (external website), rent a place to live and pay taxes.
The D number consists of 11 numbers. The Norwegian Tax Administration is responsible for the scheme with identification numbers in Norway (external website), including D numbers.
You can read more about D numbers on the Norwegian Tax Administration's website (external website).
Then you may be entitled to get a national identity number.
The Norwegian Tax Administration assigns national identity numbers and decides whether you meet the conditions for being registered as a resident in Norway. If you are assigned a national identity number, you should use your national identity number instead of your D number (external website).
Suppose you have been granted a residence permit for six months or more, and you think that you should have been registered as a resident in Norway and received a national identity number instead of a D number. In that case, you can report a move to Norway (external website)
A DUF number is not the same as a D number. The DUF number is your registration number in UDI’s registration system (external website).