The Platform
IMail Server is designed for use on an Intel Pentium-class PC running Microsoft Windows NT 3.51 or later with Service Pack 3 or higher. According to Karp, IMail v6 also runs on Windows 2000. "All our software runs on Windows 2000 just as well as it runs on NT, but we haven't yet modified IMail to take advantage of new features like Active Directory."

Ipswitch says that a single IMail server can support over 100,000 accounts and a million messages per day. But actual capacity depends on both platform and usage patterns. To support 250 POP users, Ipswitch recommends at least a Pentium 100MHz with 64 MB RAM and 2 GB of storage. Add another 4 GB if you plan to support clients who leave mail on the server. Larger installations can start with heftier platforms and set up "peer" servers that share the workload within a single domain or across several domains.

According to Ipswitch's Karp, "Most of the ISPs using IMail are small-to-medium ISPs in vertical and regional markets. Some use IMail exclusively, others have a mix of IMail and sendmail. The typical message volume is in the high thousands (5-8K) per day. Several ISPs use IMail to support tens of thousands, and just a few are over 100K. Our record is half a million messages per day with one customer."

When used for external mail, IMail Server also requires dedicated or dial-up Internet access. Dial-up servers require manual or scheduled connections (IMail won't initiate the call) and an upstream SMTP server to spool mail. Dial-up configuration is irrelevant for most ISPs. But even ISP servers will need a modem for IMail to send pager notifications or faxes (see Monitoring).

Protocols and Services
IMail Server supports all the standard mail protocols: Simple Mail Transfer Protocol (SMTP), Post Office Protocol v3 (POP3), and Internet Message Access Protocol v4 (IMAP4).

Users can download mail with any POP3 client (e.g., Eudora, Netscape, Outlook, or the built-in diagnostic IMail Client). Or they can access mail on the server with any IMAP4 client or IMail's own Web Messaging browser-based client. For added security, clients can be authenticated with SMTP AUTH, APOP, or CRAM-MD5, and web traffic can be encrypted with SSL v3. Mail-to-Fax (a separately-purchased $195 option, not tested) supports incoming mail message forwarding to fax machines.

IMail includes a Lightweight Directory Access Protocol (LDAP) v3 directory that stores user information. Alternatively, users can be stored in the NT User Database or any ODBC external database. IMail's LDAP, Finger, and WhoIs servers make user information publicly available on the Internet, but admins and users retain control over what gets published.

IMail can be configured to monitor all of these services—and other services required by mail, like DNS. IMail can automatically restart failed services and notify the administrator by mail, beeper, or alphanumeric pager. Services can be stopped, restarted, and reconfigured with a local IMail Administrator program or by accessing a forms-based IMonitor applet from any browser.

 

Introduction <	Customizable Web Mail
The Platform/Protocols & Services	Account Administration
> Installation & Integration	Virtual Domain Administration
Server Management with IMail Administrator	Security, Anti-Relay, Anti-Spam Features
Keeping an Eye on Your Server	Automated List Server/Parting Thoughts