Creating and Managing Accounts

Every network operating systems have built-in applications which allow the administrator to manage user and group accounts.
For example Windows NT has User Manager for Domains while NetWare has NWADMIN / NETADMIN.
The user needs to have administrative privileges before it can manage accounts on the system.

Default User Accounts
Most of the network systems have default user accounts that are created at the time of installation of the operating system.
Along with the user account and administrative account in some cases the guest group is also installed to provide minimum access to the resources for occasional users.

Administrative / Supervisory Account

Administrative account which had access to all services and resources on a server is available by default on all server based network operating systems.

These accounts are normally used when any security or configuration related task has to be performed on the server.

Administrator can also create other users with rights which are similar to that of an administrator.

Note: It is recommended that limited number of administrator accounts should be made as they are potential security loopholes.

User Level Security , Server Based Security

User Level Security
It is normally used on server-based networks where the administrator shares resources like folders and printers and makes them available for network users.
The resources can be protected by using high security option where each user has to logon to the system and have the rights to use the resources.
This type of security is available in Windows NT, Netware and Unix based systems.

Server Based Security
The user needs to supply a username and password to log on to the network which is then compared with the servers security database to authenticate the user
The username and group membership of an authenticated user is stored in an access key generated by the server security service or S3.
All resources on server-based systems have an access list which contain entries for all users and groups.
These entries have permission to use the resource thus controlling the access to resources.
The access list also contains the level of access available for each entry.
Whenever a user attempts to access a resource S3 matches the users access key with the entries in the list to decide if the user has permission on a resource and up to what level.

C2 security
C2 grade has been made mandatory by the US Government for all network operating systems to ensure at least some amount of security in computers.
The C2 grade has been decided by the National Computer Security Center which also defines other security levels and features.
Microsoft Windows NT and Novell NetWare 4.x have got C2 grade certification from the US Government.

Network Operating System Security

Network operating system use one of the two security models:

Share level security

User level security

Share Level Security

It is often used on peer-to-peer networks where each user can decide which resources of the machine should be shared among other users on the network.

The shared resources can be protected from other users via passwords as a mean of authenticating the user requesting the resource.

For example A windows 9x machine can provide the following access privileges when sharing a folder:

Read-only access based on passwords or without a password.

Full access based on a password or without it.

Choice between both access levels depending upon the password entered by the user requesting the resource.

The owner can also secure resources like printers with the help of a password.