SMTP Mail Servers for NT

Get a head start evaluating Internet mail packages

Internet mail with Windows NT? You bet. And my tests showed that Internet mail can be easy with packages such as Post.Office for Windows NT (Netscape Mail Server for NT), MetaInfo Sendmail with POP3, NTMail, Krypton Internet Mail Server (KIMS), and Ipswitch Imail. KIMS is the only product that provides true security between servers across the Internet. Imail strikes a good balance between ease of administration and feature set. Each package has strengths and unique qualities. Your task is to select the package that best meets your needs. So you have to evaluate your requirements and line up the products head to head with them. This cruise through the Internet mail course gives you a head start in the evaluation race.

Serving Up the Mail
To understand how Internet mail packages work and which one is best for you, you need to know about the basic transport mechanisms they provide for mail delivery. Internet mail's two major protocols are Simple Mail Transfer Protocol (SMTP), ordinarily for mail between servers, and Post Office Protocol 3 (POP3) for client/server connections. You usually need both.

The SMTP server sends and receives mail for your users and stores it locally. This server also listens for connections from other SMTP servers. The servers connect via TCP/IP port 25 using Telnet--the same service you can choose for an interactive session with a host somewhere on the Internet. Once you connect, a simple text-based exchange transfers the mail. This push protocol works reasonably well for servers that are always available.

In contrast, for machines such as workstations that can use Remote Access Service (RAS) to collect mail or that aren't always turned on, SMTP is inappropriate. Instead, to let the receiver decide when it wants the mail delivered, these workstations need a pull protocol. That's where POP3 comes in. It lets a client connect to the server and receive mail on demand.

Besides providing the basic transport mechanisms for mail delivery, an Internet mail package needs to perform other essential functions efficiently. How the administrator needs to add, configure, and remove users is crucial, too. Even if the server runs perfectly, if it's difficult to administer, it won't work well for you. Another consideration is that users can best handle some aspects of their accounts, so you need to know whether the server lets them. Also, the server needs to provide automation tools such as mailing lists and mail robots.

All the products I tested worked as advertised, sending and receiving mail through SMTP and POP3 correctly. All the POP3 servers worked properly with both Microsoft Exchange and Eudora as clients. Although I couldn't test scaleability, all the products performed well, and none used CPU excessively. These products differed in installation, configuration, and features. Post.Office is by far the easiest to install and configure, but it is nowhere near as rich in features as NTMail, which is well integrated into NT. NTMail's installation went well and the product lets you make the most of its capabilities and those of its companion, NTList (an email list server). Be aware that NTMail's learning curve is steep. MetaInfo's implementation of Sendmail works well, but it seems best suited to UNIX users moving to NT.

Finally, note that all the products I tested are dedicated mail servers. If you're implementing a broader-based solution (e.g., a Web server), you'll find that some Web server products include a mail component. For example, Interware by Consensys is a broad-based Web server product that includes SMTP and POP3 services. Also note that you can implement an SMTP gateway instead of a native SMTP server. In this case, the SMTP mail is rerouted into another mail system, such as Microsoft Mail. See the review of MailNet on page 31 for an example of such a gateway product.

Post.Office/Netscape Mail Server
When Netscape Communications wanted to license a mail server, the company chose's Post.Office. Netscape and offer this product in two incarnations, one for each company:'s is Post.Office, and Netscape's is Netscape Mail Server for NT. Either way, it's slick and easy to use.

Each company has its own packaging of the product. The version comes in single-platform versions--Alpha, Intel, or MIPS--on floppy disks. ( also plans to provide a bundled version.) The spiral-bound documentation is good. It introduces the SMTP and POP3 protocols and gives step-by-step instructions for several typical system configurations. The approach to installation can be a bit annoying if you want to simply get to it, but the instructions will be helpful if you need some hand-holding. Netscape's package provides the code on CD-ROM and bundles it for both the Intel and Alpha hardware platforms. Netscape's manual is perfect-bound, but it's otherwise similar to's.

Installation is easy. The installer, InstallShield, has a wizard interface to navigate the process, which takes fewer than 10 minutes (although if your installation needs name servers, configuring them can require up to an hour).

The first installation step is to agree to a lengthy license agreement (if you read it, you'll double your installation time). The server can run either on its own account or on the NT system account. The installer asks whether you have created an account; if you say no, the installer launches User Manager. After you enter the usual name and company information, the installer asks the name of the domain that the server will service, the port that the integrated Hypertext Transfer Protocol (HTTP) server uses for management, and a password for the administrator account. The default port for HTTP is port 80, but if the machine has an existing Web server, you can choose a different one.

After you specify the target directories, the installer copies files and makes the necessary Registry entries. That's all. The installation is complete. Now, you need to create the user accounts.

The installer also acts as an uninstaller. It does a clean job of removing the server, if necessary.

An impressive aspect of these packages is their configuration utility--your Web browser. The product uses Hypertext Markup Language (HTML) forms to manage the server, including giving users access to account configuration. To create and manage user accounts, you can get and fill out several forms that cover all the topics an administrator needs to deal with. You can access these forms from a main Web page by connecting to the server using the port number you assigned. As an example, Screen 1 shows the Account Creation Form. These packages support a finger server that you can turn on or off, multiple delivery addresses, and domain-based security. You also get an automatic reply capability that includes vacation, reply, and echo modes. For tighter security, you can restrict access to any account by domain. Once you create an account, users can access certain aspects of its configuration through the Web browser interface.

The Information Form provides a way to change passwords and finger replies. A user can set the auto-reply to vacation mode and enter the text. You can forward addresses, as with a UNIX .forward file.

With other forms, the administrator can configure security, including setting access limits to the configuration tool by domain. This feature can prevent outside users from accessing administration, even if they know the password. Configuration by email, is a feature that the administrator can enable or disable from the Security Page.

The SMTP Channel Options Form lets you set up an SMTP routing table, so you can direct mail to smart hosts that can deliver mail your server can't manage. You can also tell your server how to behave when it receives a message to an unknown local address.

All the Basic Features
Both versions are impressively easy to install and configure. They offer all the basic features you need in an SMTP/POP3 server, lacking only optional components such as mailing lists. The packages run well under NT, and you can administer them from any machine with a Web browser. Post.Office is available on UNIX platforms, too. I find that these packages are the best choice for getting Internet mail up and running easily, particularly for the first-time mail administrator.

MetaInfo Sendmail with POP3
MetaInfo's approach to providing an NT mail server was to port the UNIX standard Sendmail program. Integration of the program into the NT environment is good, but Sendmail still has the flavor of its UNIX past. So although it's less friendly than Post.Office or Mail Server, Sendmail can be an excellent choice for UNIX administrators adding NT to their enterprise.

The product comes without printed documentation and only a small readme.txt file on the media. This file prints out on four pages that cover basic installation and configuration. The version I have is on one 3.5" diskette in a CD jewel case. The insert in the case implies that the product is supposed to ship on CD-ROM or diskette.

You need some experience with SMTP to work with this product. However, after installation, you can access an extensive Help file in Windows Help format.

InstallShield and a Wizard help you install Sendmail. The first operation in the installation is branding the disks with your username and serial number. If you don't enter a serial number, the product installs as a demo.

The installation program prompts for the machine's domain name. On my machine, the program made an odd guess, combining the NT computer name and the TCP/IP domain name.

The installation process lets you select the account under which Sendmail will run. The default is the Administrator account, but a pulldown box lets you choose from any existing account. The account you select must have administrator privileges.

Once you specify a target directory, the installer completes the installation. Completion includes copying files and creating a Program Manager group for quick access to the Control Panel applets that manage the Sendmail and POP3 servers.

Sendmail also has an uninstaller. It works well, cleanly removing the application and Program Manager group.

Sendmail's configuration differs dramatically from Post.Office's. Sendmail is integrated into the Registry and requires an existing user account for each mail user. You add an account to a group called POP3 so users can log in to the POP3 server to retrieve mail. This approach is fine if all users are also machine account holders. If not, this requirement adds a complication.

The biggest hint that UNIX is alive and well inside Sendmail is that configuration uses a SENDMAIL.CF file. Screen 2 shows the configuration dialog, which sets various parameters for server behavior. Its contents are typical of UNIX--hard to understand and very picky about format. If you're a UNIX administrator, this file has the advantage of being a standard SENDMAIL.CF file; if you're not, it means a steep learning curve.

UNIX Shops Adding NT
MetaInfo's Sendmail with POP3 for Windows NT is an excellent choice for UNIX shops adding NT. This product will be familiar to UNIX administrators, and it takes advantage of the NT Registry for user information and runs as a full-fledged service. If you aren't familiar with UNIX, this version of Sendmail will probably not be a first choice. Either way, the product installs easily, works well, and can reduce the work of creating users if all users have accounts on the server machine. (MetaInfo promises to release a fully Windows-oriented version next.)

NTMail (and NTList)
NTMail can be overwhelming. The product offers so many capabilities that you can have trouble getting a firm footing when you first encounter it. But it's worth the trouble. NTMail provides an excellent set of tools for sending, receiving, and managing Internet mail under NT. I'm glad the product is available for free testing, because using it is about the only way to become acquainted with it.

NTMail distribution is exclusively over the Internet; a copy of the product (a .ZIP file of just more than 2MB) is available from By specifying NTMail with a Web search engine, you can find NTMail on some mirror sites. On these sites, you'll find testing keys that enable the product for 10 users. If you need to test the package for more users, you can request a larger key by filling out a form at the Web site.

Although NTMail comes with no printed documentation, you get Microsoft Word-formatted files--each about 6MB!--that document NTMail and its Internet list server, NTList. The NTMail manual file has 100 pages and is nicely laid out. The quality is the same as that of the printed documentation you get with other products. When you order NTMail, you can get a printed manual for $50. This manual offers both a fast track section and a step-by-step explanation. The documentation is complete and of high quality.

Basic installation is straightforward. First, unzip the distribution file to a temporary directory. Then start the installer (setup.exe). An initial screen requests the key. Entering it is probably the hardest part of installation. The key is a mix of upper- and lowercase text and symbols. A Test button lets you check proper entry of the key before proceeding and ensure that the key provides sufficient capacity. Because the key is so difficult to type, a good idea is to select and copy it after you enter it, in case you need to restart the installation. NTMail installation doesn't use a wizard, so you can't return to a previous dialog to correct data entry.

All information--key, branding, domain, and target directory selection--is in the initial dialog. NTMail correctly determined my domain name, but chose the small DOS partition on my machine for the installation directory. Watch for this problem and change the drive if necessary. Because of the online documentation and extensive product feature list, NTMail requires much more disk space--30MB--than its competition. Be sure you have enough space available before you start installing.

Once the file-copy process is complete, the installer updates the Registry and adds a couple of counters to the NT Performance Monitor, a nice touch. Setup pauses for confirmation before it updates the Registry. Then, Setup offers to start the NTMail server for you.

Among the files NTMail installs are three Control Panel applets: NTList, NTMail, and NTMail Users. These applets accomplish all direct server administration. NTMail also supports mail-based administration, which is particularly useful for end users. They can set up mail forwarding and vacation messages, for instance.

The documentation includes examples of using Web pages to send control messages to the server with Mail To:. So, although NTMail doesn't directly support Web browser access, with a little work, you can use it over the Web.

Becoming a competent NTMail administrator takes time. Most things you will ever want to control are configurable, as you see in Screen 3.

The product is highly automated. The main configuration activities are user account creation and various naming adjustments for such things as aliases and domains. The main NTMail Control Panel applet offers access to all functions, and the NTMail Users applet offers a subset.

At the cost of ease-of-use, this product departs from the pack by providing more capabilities. NTMail offers all the basic functionality of the competition--and more. For example, one potentially powerful feature is Auto-launch, which lets the server launch an NT application in response to an email message. So an NT administrator can control a variety of programs on an NT box without a realtime connection to the machine. Only your imagination limits the potential for Auto-launch.

The biggest difference between NTMail and the other servers in this article is its direct support of a sophisticated Internet list server, NTList. A list server (or list processor) automates the mailing of messages to a list of recipients at one address. Although this process sounds simple, managing a large list is not trivial. Issues of subscription and desubscription, moderation (determining whether a message will make it to the list), limitation of content and size, and other user-management features come into play. NTList addresses all these issues admirably. Although NTList is a separate product, it's bundled with NTMail, and you install them at the same time. If you need a list server, this well-planned application will fit the bill.

NTMail also supports automation in the form of mail robots. These applications give you several ways to process mail messages. Three examples are available on the distribution Web site: Hypermail, Dumpmail, and Conpage. Hypermail converts a sequence of messages into a Web page, allowing digests of mailing lists to be Web-accessible; Dumpmail puts messages into an arbitrary directory; and Conpage accesses a paging terminal and sends a message based on the subject line.

A Power Tool for Mail
NTMail and NTList are an administrator's power tools. They can do almost anything with email.

List services, robots, and extensive configurability make this product well suited to an enterprise that heavily relies on email for communications. NTMail is a professional Internet mail suite that won't disappoint you.

Krypton Internet Mail Server
The distinguishing feature of KIMS is that it has secure Internet email. By using Extended SMTP (ESMTP), KIMS can provide mail encryption across the Internet without requiring a special client. Two servers negotiate the encryption when they encounter each other.

Clearly KIMS developers focused on the product's technical quality. The installation is functional, but bare bones. It uses Microsoft Setup and asks only for a directory and a few options before completing. The default directory is \SMTP, and the entire installation in this directory takes about 170KB. The installation program starts the KIMS service before end. Setup also acts as the uninstaller.

You administer KIMS through a simple Control Panel applet that is also a statistical monitor. It provides regularly updated numbers on mail-in, mail-out, and server up time. You can leave the applet running on the desktop to keep track of the server.

You can enter a few parameters from the applet, as Screen 4 shows. You can specify an outgoing gateway. If you want your mail routed through a particular gateway rather than delivered directly, you define that gateway here. Three other parameters relate to the Outgoing Mail Queue: OMQ Interval specifies how often you want the server to check the queue for outgoing mail, OMQ Retries tells the server how many times to attempt delivery before giving up, and OMQ Retry Delay defines the time between tries.

Checkboxes let you enable or disable server features. The Secure checkbox toggles the KIMS secure mail features. If you turn off this box, KIMS behaves as an ordinary SMTP server. KIMS supports both node- and domain-relay functions. If you enable node relay, the server forwards mail to a different server in your domain. If domain relay is on, the server forwards mail to another domain. The default, which defines normal server operation, is to have both relays on.

Turning off ESMTP will also disable secure mail. This consequence is unintended, because one use of ESMTP is to negotiate encryption functionality. The ESMTP-based EXPN function lets you expand mail groups. KIMS is tightly integrated into NT's Registry, so KIMS can use NT groups as mail groups. You can disable this feature for a more secure, though less convenient, arrangement.

Features and Functions
KIMS supports mail forwarding and auto-reply. Forwarding works like it does in the UNIX version by looking for a file called .FORWARD in the user's directory. This text file contains only the address for forwarding.

KIMS also lets users configure features by email. A special user called MailBot receives and processes control messages to configure user accounts. To use MailBot, the user sends a specially formatted message to [email protected] The subject line contains a verb, set or clear, and a parameter, forward, reply, or password, to act on. The values for the command go in the body text. The reply function is auto-reply. The password function lets users set a POP3 password different from their NT account password. Anyone who will use the POP server must have the Logon Locally attribute set. A good idea is to create a POP3 user group and set the attribute for the group.

User reports I've heard say performance is excellent. The developers carefully wrote KIMS to use only Win32 calls, so it's a true and complete 32-bit application that can take full advantage of NT's multithreading capability.

Security Is the Key
The obvious advantage KIMS has over the competition is its ability to use public-key encryption to transfer mail securely across the Internet. When two KIMS servers meet, they announce their encrypted mail capability and negotiate an encryption level. Then they can exchange keys and encrypt and decrypt the mail. Traffic on the Internet is encrypted, but traffic from server to client is not. A sniffer on your LAN can read the plain text mail.

KIMS comes in three versions: Standard, which has no encryption but supports ESMTP; Domestic, which supports 40- and 80-bit key encryption and both single and triple DES standards; and Export, which can do only 40-bit key encryption. Legal limitations exist on the export of encryption technology, so the 40-bit key support of the Domestic version is for compatibility with the Export mode. The KIMS implementation of secure mail--called Secure SMTP, or SSMTP--is proprietary, but it's based on standard ESMTP protocols, so the product is 100% interoperable with other SMTP servers.

Secure Mail Across the Internet
KIMS is technically excellent. It's unique in providing true secure mail across the Internet, allowing users to be comfortable with the Internet as an enterprise mail transport. Because the focus is on technical quality, KIMS is less slick than its competition. But if you need high reliability, top performance, and secure mail transfer, choose KIMS.

Ipswitch IMail
Ipswitch IMail is a thorough package that offers many of the same features as NTMail. However, Imail is easier to learn and administer than NTMail. IMail includes a variety of servers besides the SMTP and POP3 servers required to do the basic job. In addition, IMail can pipe mail messages into external programs for automated mail response, list server, and other messaging applications. Unlike the other products reviewed here, IMail has a mail client.

IMail uses Microsoft Setup for installation, which is a quick and easy process, with two dialogs for information. Setup needs to know your machine's fully qualified domain name and the target directory for installation. It defaults to \IMAIL in the first partition. Once the file-copy procedure is complete, Setup reminds you to make a new emergency repair disk because IMail adds a security key to the Registry.

You administer IMail through a combination of the IMail User Manager for adding and managing users and a Control Panel applet that starts, stops, and configures the various servers. The User Manager is a two-pane application. Users are in the top pane, and mail aliases are in the bottom. Three selections on a button bar let you add, modify, or delete a user. Selecting Add or Modify invokes a User Properties dialog that you can use for either function.

IMail comes with a finger service that lets a finger client connect to and retrieve information about a particular user. The traditional UNIX finger supports a user-generated text file called a plan file. IMail handles plan files, storing them in the user's directory as PLAN.IMA instead of as traditional UNIX .PLAN files. You can create and edit .PLAN files from the User Properties dialog. One unique feature of IMail is a simple "rules" capability that lets the server direct mail according to the content of the mail's header. The rules are simple searches in a message's from, to, subject, or sender lines. To manage mail addressed to a particular user, IMail follows the rules in the RULES.IMA file in the user's directory. A rules editor is part of the User Properties dialog.

In addition to supporting the traditional auto-reply, IMail has a more sophisticated version called InfoManager. InfoManager can respond to messages that include a "subcategory" designation. For example, if your organization uses an [email protected] account to send information automatically, InfoManager can expand the system's capabilities by offering subcategory responses. A typical scenario involves sending a reply to the info account with a list of possible messages. InfoManager instructs the correspondent to send mail to [email protected] for support and [email protected] for sales. These messages end up in the same place, but InfoManager replies with a different message for each. You can combine this capability with rules to make it even more powerful. This useful feature will make setting up an email-based information system quick and easy for any organization.

The User Properties dialog lets you disable the finger server on a per-user basis. This capability is a nice confidentiality feature.

Another interesting approach in IMail is a remote configuration program called IMail User Utility. It lets users modify their accounts without administrator intervention. The program communicates through TCP/IP, so you can use it anywhere you can make a connection to the server. The User Utility looks a lot like the User Properties dialog, though it lacks a few options. Users can change their POP server passwords (unless you go through the User Manager and disable this capability user by user) and modify their forward and plan files. With the rules editor, users can set rules for mail delivery and enable or disable the auto-reply program. Users can do almost anything without help.

The IMail Control Panel applet involves more than just SMTP and POP servers. You see six buttons, each for a service. They include a standard UNIX Whois server, a finger server, a password server, and a log server. The password server provides support for the Eudora mail client password capability. This feature is good if your organization has chosen Eudora. The Log Server logs server activity, and you can view its log file from this dialog. Screen 5 is an example of one of the six service dialogs you can access from the applet's main screen.

Because IMail can pass mail to other programs, you can use it with a list server. List servers automatically receive and distribute mail and let you conduct discussion groups. Unlike NTList, the IMail list server is very simple, but it's still functional, and useful. If you want to write a more sophisticated list server, Ipswitch includes a .ZIP file with full source code for the list server.

Thorough Selection of Servers
Ipswitch IMail is a solid product with a thorough selection of servers and usable utilities. It is not as slick as Post.Office or as automated as NTMail, but when you consider learning curve and sophistication, IMail's cost/benefit ratio is excellent. The InfoManager feature alone will sell this product to some users. IMail is easy to use and powerful.

Post.Office for Windows NT * 805-882-2470
Email: [email protected]
Price: $495
$450 (FTP download)
Netscape Mail Server 1.1 for NT
Netscape Communications * 415-937-2555
Email: [email protected]
Price: $995
MetaInfo Sendmail with POP3 for Windows NT
MetaInfo * 206-521-2600
Email: [email protected]
Price: $495
Internet Shopper
Email: [email protected]
Price: 2 users $60; 3-10 users $200; 11-49 users $350; 50+ users $500
Krypton Internet Mail Server for Windows NT 3.51 (1.0b)
Krypton Communications * 770-352-9704
Hayes Computer Systems * 904-297-0551
Email: [email protected]
Price: Standard $500 (no encryption, no user limit); Export $1000 (secure but 40-bit RC2); Domestic version $1000 (40- and 80-bit RC2, and single or triple DES)
Ipswitch IMail Server for Windows NT 2.61
Ipswitch * 617-676-5700
Email: [email protected]
Price: $695 (includes 10 copies of IMail Client)
Consensys Computers * 905-940-2900
Email: [email protected]
Web: http://www.
Price: $1495
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