Which characters are acceptable for a computer name?

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Here is the characters that is acceptable in making computer name:

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Windows Computer Name: Best Practices and Recommendations


After a new installation of Windows Server (e.g. Windows Server 2019) or Windows client (e.g. Windows 10 Professional), the computer is assigned a random 15-character computer name, which looks something like this: WIN-VPLD4SB9KWG. The technical name for the computer name is NetBIOS name. NetBIOS is an abbreviation for Network Basic Input/Output System and it’s used by applications to communicate over a local area network (LAN). Simply put, a computer name (i.e. NetBIOS name) is used by computers to communicate over a LAN.

Here are some useful points to remember:

Every Windows computer must have a computer name, also known as NetBIOS name, which can be between 1 and 15 characters long.
Every Windows computer must have a hostname and an IP address to communicate with computers across the Internet.
There is no difference between the term computer name and NetBIOS name. They are exactly the same thing.
By default, computer name, NetBIOS name, and Hostname of a Windows computer are exactly the same and you should keep it that way.
Hostnames are used by DNS Servers for name resolution on the Internet and on the LAN. NetBIOS names are used by the WINS Server only on the LAN. WINS is an older technology and it’s rarely used anymore.

Computer name and NetBIOS name are the same. NetBIOS name is the technical name, but people often find it easier to use the term Computer name.
Allowed Characters in NetBIOS Names

A NetBIOS name consists of 16 characters. However, the 16th character is reserved for NetBIOS Suffix, which identifies the service type for the registered name. You can type nbtstat -n (make sure n is in lowercase) at the command prompt to see the NetBIOS name, type, and status in a NetBIOS local name table. The 16th byte will tell you what type of service is running on the computer (e.g. RAS, workstation, etc.). Check out the NetBIOS Suffix Definitions table at the end of this article. I am adding it as a reference here. Because the 16th character is reserved, the computer name can only consist of 15 characters. According to Microsoft, the following characters are allowed in NetBIOS Names.

All alphanumeric ASCII characters (letters A-Z and numbers 0-9)
Although numbers are allowed, you can’t have a NetBIOS name that only contains number (e.g. 1234567) due to a DNS restriction.
Although underscore (_)can be used in a NetBIOS name, it’s not allowed in a DNS hostname so your computer will fail to communicate on the Internet. There’s more on this later in this article.
Although hyphen (-) is allowed in a NetBIOS name, I don’t recommend it. There’s more on this in the next section.
Period was allowed in older operating systems (except at the beginning of a name), but Microsoft has discouraged using a period since Windows 2000.

Disallowed Characters in NetBIOS Names

You cannot use the following characters in a NetBIOS name:

period (.)
backslash (\)
forward slash (/)
colon (:)
asterisk (*)
question mark (?)
quotation mark (“)
less than sign (<)
greater than sign (>)
vertical bar (|)

Disallowed Characters in Hostnames

As I mentioned earlier, the NetBIOS name and hostname are the same by default. This means you need to make sure that your NetBIOS name is using characters that are allowed in DNS hostnames. This is an important concept to grasp. If I am not making it clear, please post a comment so I can clarify it. The following characters are not allowed in the DNS hostnames, therefore you should not use them in NetBIOS names. Yes, if you use these characters you may get away by using them on LAN, but your computer won’t be able to communicate on the Internet.

comma (,)
tilde (~)
colon (:)
exclamation point (!)
at sign (@)
number sign (#)
dollar sign ($)
percent (%)
caret (^)
ampersand (&)
apostrophe (‘)
period (.)
parentheses (())
braces ({})
underscore (_)
white space (blank)

Other Considerations for NetBIOS Names

Here are some additional notes regarding the NetBIOS names.

The first character in a NetBIOS name must be alphabetic or numerical, not a special character.
Although numbers are allowed, you can’t have a NetBIOS name that only contains number (e.g. 1234567) due to a DNS restriction.
The last character cannot be a minus sign or a period.
You cannot use any of the 2-character Security Descriptor Definition Language (SDDL) user strings listed in well-known SIDs list. According to Microsoft, it will make “import”, “export” and “take control” operations fail. Consider this a banned list of NetBIOS names so don’t use a computer name AU, CA CO, etc.

BEST PRACTICE: I recommend you only use letters A-Z and numbers 0-9. Do not use a period, underscore, or a hyphen in a NetBIOS name

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