IT Services



Naming Standards for Windows PCs on the Oxford University Network


Contents

If you are configuring PCs to use the central OUCS WINS servers, their computer (or NetBIOS) names must be unique within the whole university.

To minimise the risk of name clashes, naming standards were developed which state that PCs should be given a NetBIOS or Computer Name which starts with an identifier that is unique to the unit where the PC is located. The list of identifiers is given here. The unit identifier can be separated from the rest of the name by a hyphen.

Further, NT domain names and the NetBIOS name for 2000 domains should be chosen carefully so as to identify your unit unambigously and avoid name clashes with other domain or computer names.

This document contains further information about the naming standards, why they are so essential and answers to frequently asked questions.



1. The Naming Standards

If you are configuring PCs to use the central OUCS WINS servers, the computer (or NetBIOS) names must be unique within the whole university. If not, name clashes can occur which result in network services being disabled on one PC. If this PC is a server it can cause major problems for many users. Therefore naming standards must be used which include a unit identifier to minimise the risk of name clashes between PCs in different units. For units who don’t use the central WINS service, we recommend at least using the naming standards for servers, in case you ever wish to use the central WINS servers (NT and 2000 server servers being either impossible or difficult to rename.)

The naming standards state that PCs should be given a NetBIOS or Computer Name which starts with an identifier that is unique to the unit where the PC is located. The list of identifiers is given here. The unit identifier can be separated from the rest of the name by a hyphen.

Further, NT domain names and the NetBIOS name for 2000 domains should be chosen carefully so as to identify your unit unambigously and avoid name clashes with other domain or computer names.

NetBIOS names can be up to 15 characters so the rest of the characters (generally about 10) can be used to name the PC or domain as you wish. Be aware that SQL 6.5 or below has problems with hyphens (there is a workaround if required.) Examples of names are oucs-fred, oucsfred, bras-tom, quee-pc023.

These naming standards replace the standards introduced in 1998 which stated that all PC names should end in .unitcode where unitcode is the unique identifier. Units currently using the old standards do not need to rename all their PCs; in fact, if you want to carry on using the old standards this is not a problem for 95, 98, Me or NT. However, the standards were revised because the original ones cannot be used to name Windows 2000 PCs, and the new standards also have advantages when naming Windows NT PCs.

If your PCs currently use the central WINS servers but are not named according to the Naming Standards, we don’t necessarily recommend renaming all your PCs unless you have problems with name clashes. In particular, never rename a server, especially a domain controller, except as a last resort, and make sure you are aware of the consequences before you do so. If you have a server that is experiencing a name clash, contact winsmaster before changing any names since it may be possible to protect that name to prevent the clash occurring. However, do start naming all new servers and workstations in accordance with the standards, and you can usually rename workstations without causing any problems.



2. How Essential is Correct Naming?

Use of the Naming Standards is essential if you use the central OUCS WINS servers (163.1.2.52 and/or 129.67.1.52) in order to avoid name clashes. If you do not use the central WINS servers, you don’t need to use these standards, and most of the time this will not cause you problems. However, while it is generally easy to rename a PC that has a duplicate name, it can be extremely difficult to rename a Windows NT domain controller, and renaming a Windows 2000 domain controller is quite simply impossible. Renaming file and application servers can also cause problems. We therefore recommended that even if you don't currently use the central WINS servers, you should at least use the naming conventions for all servers, and choose sensible domain names, just in case in the future you want to switch to using the central WINS service.

NB: It seems to be a common misconception that using of the central WINS servers makes conforming to the naming conventions unnecessary. This is not true! Using the central WINS servers actually makes conforming to the naming conventions essential. This is because if your PC tries to register a name with the central WINS servers, and that name already exists in their database, the registration request will be refused, and network services on that PC disabled, which for servers can be particularly catastrophic.



3. Why did we Change the Naming Standards

Until Windows 2000 was released, Windows PCs generally had two distinct names. The first is the NetBIOS or Computer name, which is generally set in the Network Control Panel under the Network Identification tab. This is the name that is registered in a WINS database if WINS is being used. The second is the DNS name of the PC (e.g. fred.oucs.ox.ac.uk) which is generally set in the TCP/IP Properties, under the DNS tab. However in Windows 2000, although a connection-specific suffix may be set under the TCP/IP Properties, most identification settings have now moved to the System Control Panel. Here you can set a Computer Name and a Primary DNS Suffix. The Computer Name is used both as the first part of the DNS name (up to the first ".") and as the NetBIOS name of the computer. This means that it cannot contain the "." character, causing the first problem with the old naming standards which required the Computer name to be suffixed by .unitcode. The second problem arises because the Computer name setting may have considerably more than fifteen characters while NetBIOS names may only have a maximum of fifteen. Hence if the name is longer, it is truncated and only the first fifteen are used as the NetBIOS name. This could lead to part or all of the .unitcode suffix being truncated. The solution to these two problems was firstly to drop the requirement for the "." character, and secondly to move the unitcode identifier to the beginning of the name.

Note that we don't require or expect computers named according to the old naming standards to be renamed.



4. FAQ

Q. I have been using the original naming standards. Do I need to rename existing PCs according to the revised standards?
A. No, this would be impractical. Just name any PCs you install from now on according to the revised standards.

Q. Do I need to rename existing NT domain controllers according to the standards?
A. Renaming domain controllers can be difficult, especially if you have a lot of NT workstations in the domain, or have some of the backoffice applications (e.g. Exchange) installed. Renaming Windows 2000 domain controllers is impossible. We don't recommend renaming domain controllers unless it is unavoidable because a name clash is causing problems, and we advise exploring other options first — email winsmaster for advice.

Q. Do Windows 2000 PCs really end up with a DNS name that contains the unit name twice?
A. Yes, unfortunately they do, but there doesn't seem to be any other option. For example, an oucs PC with the NetBIOS name of oucs-fred will have the DNS name oucs-fred.oucs.ox.ac.uk.

Q. Does the NetBIOS name need to be the same, or similar to, the first part of the DNS name?
A. Only on Windows 2000. On Windows 95, 98, Me and NT the NetBIOS name and the DNS hostname (up to the first ".") can be completely different (NT will try to make them the same but it can be pursuaded otherwise). However in Windows 2000 Microsoft has linked the two names so that the NetBIOS name and the first fifteen characters of the DNS hostname (up to the first ".") are identical. Bear in mind that this is the DNS name that the computer thinks it has — there is actually nothing to stop you registering a different name against its IP address through the normal DNS update mechanisms. However, it is probably good practice to ensure that the PC knows the same DNS name for itself as the one that you register (and that the rest of the world therefore knows), and especially so for domain controllers.

Q. What characters are valid in NetBIOS names?
A. According to Microsoft, “a computer name can be up to 15 alphanumeric characters with no blank spaces. The name can contain the following special characters: ! @ # $ % ^ & ( ) - _ ' { } . ~ and the following characters are not allowed: \ * + = | : ; " ? < > ,” (see Q188997 - Microsoft NetBIOS Computer Naming Conventions.) However in Windows 2000, DNS naming restrictions also apply. This means that on Windows 2000 PCs you should only use alphanumeric characters and dashes (hypens “-”) in the Computer Name. Windows 2000 will actually allow you to enter some other characters (although it will warn you about using them) but I would recommend avoiding other characters since you will not be able to register names that contain them in the DNS.

Q. My unit uses a different naming scheme; can I continue to use it?
A. A number of units have developed their own naming conventions (in many cases this happened before the central conventions were developed). Where these contain some form of the unit name their use is unlikely to result in name clashes. However it may be a good idea to use the central conventions when naming any new domain controllers or servers.

Q. Can I check if a name is in the central WINS database?
A. You can’t check this yourselves. However, if you email the name that you want to check to winsmaster we will check for you. If you want to check that a WINS registration is correct, or for a name clash, please also include the IP address that name should be registered under.

Q. Where do I set the computer name and DNS suffix in Windows 2000?
A. Open the System control panel and go to Network Identification, then Properties. Set the Computer Name here (this is the NetBIOS name and the first part of the DNS name). Go to More to set the primary DNS suffix (i.e. the rest of the DNS name, e.g. oucs.ox.ac.uk).

Q. Where do I set the computer name Windows 95, 98, Me and NT?
A. For all of these operating systems, open the Network control panel and go to the Identification tab. For NT you then click on Change to change the Computer Name. For the other operating systems you just type the name straight in.



5. Further Information