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Which server is best when mixing Windows NT into a Solaris network?

And how do you do it?

By Shari L. Jones

August  1999
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Several months ago, Shari addressed the issues involved with integrating a Windows NT Workstation into a Solaris network. In this follow-up to that article, she looks at the server side and details the implementation of basic Windows NT services, such as file and print sharing, into your Solaris environment. (2,700 words)

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As a network administrator with the goal of integrating Windows NT services into a Solaris network, you're faced with several key considerations when choosing the right configuration for your network.

Your number one challenge is to meet the computing needs of all corporate users and provide fundamental system services offered by both Windows NT and Solaris. Secondly, you must maintain the high-level security offered by Unix while keeping downtime for network maintenance to a minimum. And finally, you must consider your server options when choosing the network configuration that will provide critical Windows NT services.

Your job as a network administrator is to make the transition to a mixed Windows NT Server and Solaris network environment smooth and transparent to Unix and PC users. Whether they're running Windows NT Workstation or Solaris on the desktop, end users should reap the benefits of the operating system they're using, and not be concerned with which server is providing critical network services. As the administrator, you must consider whether Windows NT Server or a Sun server running something like Sun's PC NetLink (part of Sun's newly announced Solaris Easy Access Server 3.0) or The Samba Group's Samba freeware is the appropriate option to provide Windows NT services. Samba, like Solaris Easy Access Server (PC NetLink), provides similar basic services to Windows NT Server and resides on a Unix server. A third option we'll discuss in this article is to run Sun's Solstice NFSTM Client, which also is part of Solaris Easy Access Server, on the client side, providing Windows NT client users with Windows NT services in a Solaris network without integrating a Windows NT Server machine.

Exploring the options
When merging Windows NT's basic services into a predominantly Solaris environment, you must first consider which configuration option is most logical for your environment. The network configuration and server you use will depend on whether your clients are primarily Unix or primarily Windows NT. Perhaps your company, with its Unix network, has merged with a company that is Windows based. Now you have a fairly even mix of both, but all clients need to be able to communicate and share network resources. In a dual environment, you must choose which platform will provide which services.

Your options are as follows:

But which configuration is best for your environment? Consider the following scenarios.

Scenario 1. Integrating Windows NT Server into a Unix environment
If your networking environment not only requires basic Windows NT services, but consists of services not easily duplicated on a Unix server, integrating Windows NT Server into your Unix network via a gateway is necessary.

Applications that run on Windows NT -- such as Microsoft BackOffice products, Microsoft Exchange, or Microsoft SQL Server -- require Windows NT Server and cannot be ported to a Unix server. In this scenario, you have no choice but to integrate Windows NT Server into your Solaris network to run these applications, but all other services can run on the Unix server.

Installing an NFS (Network File System) gateway on Windows NT Server and connecting the server directly to your Solaris network allows your Windows NT clients to communicate with the Windows NT Server machine using their "native" SMB (Server Message Block) protocol, and the Windows NT Server machine to communicate with a Unix server using NFS. (Both protocols are explained in detail later in this article.) Installing the software doesn't require you to make changes to the Unix server or Windows clients. The gateway software handles the conversion of SMB messages to NFS messages, and vice versa, allowing Windows clients to communicate with the Unix server.

Integrating Windows NT Server into a Solaris environment requires administrators to consider many architectural differences between the two operating systems. For a quick, yet detailed description of the various steps required in this process, O'Reilly & Associates and Hewlett-Packard Education jointly offer a series of handbooks entitled The Complete Windows NT & Unix System Administration Pack. (See Resources.)

Scenario 2. Creating a 'dual-personality' Unix server
If you have a mixed Windows NT and Unix environment and require only basic Windows NT services, you can probably do without integrating Windows NT Server. However, if additional, customized NT services are required that are not provided by Solaris Easy Access Server, Windows NT Server is required.

You can install software on a Unix server that imitates the basic Windows NT services. Several software options are available on the market today that allow a Unix server to provide basic Windows NT services. Among the more popular options are Samba and Solaris Easy Access Server with PC NetLink.

Based on the demands of your end users and the network configuration, you can determine whether or not you should go with this scenario. Use the checklist below to determine if your environment warrants installing software on a Unix server to provide basic Windows NT services in a Solaris environment:

If your networking environment meets the above criteria, you should consider creating a dual-personality Unix server -- one that provides standard Unix services and has software that allows the server to provide basic Windows NT services to Windows NT clients. Nothing changes for Unix clients. The operating system running on the server providing the services is transparent to the Windows NT clients.

Solaris Easy Access Server with PC NetLink provides an alternative to Windows NT Server when integrating basic Windows NT services into a Solaris or a Windows NT network. Solaris Easy Access Server with PC NetLink allows Sun Enterprise servers and the Solaris operating system to support Windows NT domains, thus introducing Unix's scalability and security into the Windows environment. Alternatively, Solaris Easy Access Server can either coexist with or replace Windows NT Servers.

Solaris Easy Access Server offers the same file, print, directory, and security services as Windows NT Server; however, it is more scalable. A Solaris Easy Access Server supports 1 to 64 CPUs versus Windows NT Server's support for 1 to 8 CPUs. Solaris Easy Access Server profits from the reliability and security of Solaris while providing Solaris administrators with more flexibility for future network growth. Solaris's scalability, along with the Solaris Easy Access Server, allows administrators to consolidate multiple Windows NT services onto fewer Sun servers than if they were providing the same services through Windows NT Servers.

Using PC NetLink
Using Solaris Easy Access Server with PC NetLink, Windows NT clients send requests for a Windows NT service, such as a printing or security service, to a Sun server; the request is sent using the Microsoft protocol. The Solaris Easy Access Server running PC NetLink understands and interprets the NT service requested, and responds to the client's request. PC NetLink is transparent to both users and NT system administrators.

Sun's server and the PC NetLink software are based on actual Microsoft NT 4.0 code licensed from AT&T, and this enables a Sun computer to plug into a Windows network, imitating a Windows NT server machine. Solaris Easy Access Server encourages administrators to use Solaris as the operating system of choice instead of Windows NT Server when Windows NT services are required.

PC NetLink allows the Solaris Easy Access Server to offer native Windows NT network services, such as naming, authentication, and file and print sharing, on fewer servers than would be possible using Windows NT servers. The software comes with an unlimited client license on new Sun Enterprise servers.

Using Samba
The Samba Group's freeware, called Samba, provides similar capabilities to Solaris Easy Access Server running PC NetLink. Running on a Unix server, it too provides basic file and print services to Windows NT clients. While Samba provides a possible alternative to PC NetLink, Sun's version now ships with Solaris Easy Access Server, making PC NetLink a more likely option in an enterprise setting.

A Unix server running Samba can send NT files to a printer or share files between Unix and NT client machines. Samba recognizes the SMB/CIFS (Server Message Block/Common Internet File System) protocol used to move Windows NT files across the network. NetBIOS message blocks don't run on Unix, so Samba provides that functionality for Unix.

With Samba, the files are converted into standard Unix files on the Unix server, and the server presents the files as SMB/CIFS to Windows clients. Samba makes the initial SMB/CIFS protocol conversion to NFS, because all Unix machines speak NFS. Thus, Samba provides the conversion needed to allow Unix and Windows NT to share file and print services.


Scenario 3. Creating a 'dual-personality' Windows NT client
If the minority of your clients use Windows NT Workstation and must be integrated into your Solaris network, you should consider installing Sun's Solstice software on Windows NT client machines. This client software provides access to Unix services from Windows NT clients. It acts on the Windows NT client side to provide basic Windows NT services in a Solaris network without integrating Windows NT Server into your network. The software must be installed on each client machine, so it's ideal in environments where the majority of the clients are Unix users and there are relatively few Windows NT client machines.

Solstice NFS Client software offers NFS file and print services for Microsoft Windows users. Its capabilities include:

Solstice NFS Client software offers a single, flexible solution set for Microsoft Windows desktop users because it is integrated into the file and print services of 32-bit Microsoft Windows platforms.

The client software supports long file names, and advanced NFS capabilities are added to Microsoft's Network Neighborhood. Through its exclusive use of the NIS and NIS+ naming services, Solstice brings additional network ease of use to Microsoft Windows users. Network resources are available to users with the single click of the mouse, without having to know where the resources are located on the network and without memorizing long path names or dynamic locations.

Solstice supports TCP/IP, which facilitates compatibility with other Microsoft networking components. For earlier 16-bit versions of Microsoft Windows client machines, a Sun TCP/IP stack is provided by Solstice.

Configuring services and protocols
After defining your environment and selecting a server, network administrators must configure the services and protocols that both operating systems require for successful integration.

Dynamically assigning IP addresses
Regardless of whether you're setting up a network consisting primarily of Windows NT or Unix servers, you should enable DHCP (Dynamic Host Configuration Protocol). DHCP dynamically allocates IP addresses to machines as they're brought onto the network. This requires that at least one Windows NT Server or Unix server act as a DHCP server to perform this function.

A DHCP server dynamically assigns IP addresses to a client. An IP address is required to communicate via TCP/IP, which is the protocol used by both Unix and Windows NT to allow two operating systems to share information.

You configure Windows NT Server to provide DHCP service by defining the IP scope and configuring leases. The DHCP server is configured using the Microsoft Windows DHCP Manager, which you access through the Administrative Tools option of the Windows Start menu.

To continue the configuration process:

  1. Select the DHCP Manager option to open the DHCP Manager window. This lists the DHCP servers available through the network
  2. Select the DHCP server that will dynamically assign the IP address to the Windows NT Server
  3. From the Scope menu, click Create to display the Create Scope window
  4. In the Start Address and End Address boxes, define the range of IP addresses for DHCP clients

Next, you must set the time frame in which the client can use an IP address. The Lease Duration area of the Create Scope window includes two options: Unlimited, which is used if the access time has no limitations, or Limited To, which allows administrators to define the number of days, hours, and minutes for which the DHCP client can use the IP address.

To define the lease durations for the clients:

  1. Select the appropriate option to configure the lease duration
  2. Click OK to define the IP scope and configure the lease duration for DHCP
  3. Restart Windows when prompted to enable DHCP

After restarting Windows, DHCP clients will dynamically obtain IP addresses from the DHCP server.

Setting up NFS services
Because Unix and Windows NT don't have compatible filesystems, you must add software that allows each operating system to understand the language of the other. Unix uses NFS and Windows NT uses SMB. PC NFS software allows your Windows NT Server to communicate using NFS. It allows Unix users to access files residing on a Windows NT Server and allows Windows users to access files residing on a Unix system. As an administrator, you must make the judgment call as to which scenario listed above is right for your networking environment.

To allow end users working from a Windows NT Workstation access to files residing on the Solaris network, the NT machine that communicates with the Unix system must have NFS services loaded. A third-party vendor typically provides NFS. The end user must have a user ID and password established on the Unix system prior to configuring the Windows NT Server for NFS.

The network configuration determines where the NFS client services are loaded, either on the Windows NT Server or on the Windows NT client machines.

Bringing it all together
Through proper planning and foresight, you can successfully integrate Windows NT Server, Solaris Easy Access Server, or Samba to provide basic Windows NT services to your end users. You must be well acquainted with your current networking environment and the configuration options available to you when tasked with providing Windows NT clients with Windows NT services in a Solaris environment.

After you select the network configuration that works for your organization, conduct an impact analysis on the network before implementing it. Preimplementation testing reduces potential downtime to users should some configuration changes be required.

Thanks to Fernando Lozano, Brian Long, Jim Wessinger, and Steven Gould for their help with this article.

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About the author
Shari Jones is a consultant for a large international consulting company. She is a technical writer and freelance journalist covering all areas of the high-tech industry.

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