Upgrading and Repairing Networks (5th Edition)

The best way to solve a problem is to take all necessary measures to ensure that the problem doesn't happen in the first place. Although it is not possible to completely eliminate every source of failed logon problems, you can do a lot to keep your network users happy by taking a few precautions :

  • Place a backup domain controller on every physical subnet ” If a network link goes down, users can still be validated by the local BDC and continue to work with resources to which they can still connect. A BDC with enough available resources can simultaneously perform the same functions as any other Windows NT Server, so if you have a server on a subnet that is offering resources and it is not already overloaded, consider replacing it with a BDC and let it serve two roles. Remember, if the server is not already a domain controller, you will have to re-install the OS and select that option during setup.

  • Enforce reasonable password policies ” Some operating systems allow you to computer-generate random passwords that are very difficult to remember. If a user cannot remember a password, most of the time the user will just write it down somewhere, which can compromise security. If you force users to change passwords too frequently, they will most likely have a hard time remembering what the recent password is, unless they write it down somewhere. If you set the account policy lockout values too low, you will find that users get locked out because of simple typing errors, and the help desk will spend a lot of time unlocking these accounts.

  • Keep track of user accounts ” You can use a paper method or an electronic one such as a spreadsheet or database. Delete accounts for users who leave the company and create new ones for new employees . Getting rid of the dead wood will help avoid confusion when troubleshooting and will help keep the SAM databases down to a reasonable size.

  • Never use generic accounts where more than one user logs in under the same username ” Though this is a tempting idea because you have fewer user accounts to manage, it can be a security nightmare if something goes wrong and you are unable to use auditing measures to figure out the who, what, and when of the matter. Also, when more than one person is using the same account to log on, it takes only one person with fumble-fingers to incorrectly type a password a few times and lock an account, also preventing others who use the same account from logging in.

To fully understand how to troubleshoot problems with logons , you should make yourself knowledgeable about the Windows NT Event Viewer administrative tool. You can find out more about this valuable utility in Chapter 47.

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