CommuniGate Pro
CommuniGate Pro is a full-featured, scalable SMTP mail and list server. Standard features include SMTP Internet mail support with extensions, Web access to mail, and support for POP3 and IMAP4 clients. The software has features to protect against unsolicited commercial email (UCE), including blacklisting and return path verification. Remote POP (RPOP) support lets users specify POP accounts on other mail servers for CommuniGate Pro to poll periodically. The RPOP feature also supports organizations that receive all user mail in a single-mailbox account (i.e., unified domainwide account) that the organization's ISP provides. RPOP periodically polls the ISP account and distributes mail messages from the unified account to users' CommuniGate Pro mailbox. CommuniGate Pro's multithreaded design supports simultaneous access to a mailbox from multiple POP3 or IMAP4 clients. You can use NT user accounts and CommuniGate Pro-created accounts to authenticate user mailbox access.
The software implements an LDAP server for access to account and other information that the Central Directory database contains. Application Configuration Access Protocol (ACAP) support lets IMAP and POP clients retrieve configuration and preference settings from CommuniGate Pro. The Password Modification Protocol (poppwd) lets supporting clients change the password for mailbox access. Because a mailbox owner can use either an NT account password or a CommuniGate Pro password for mailbox access, poppwd checks to see which password is in use, then changes the password to the new password. CommuniGate Pro supports a number of secure client authentication protocols, including Authenticated Post Office Protocol (APOP), IMAP-AUTH, and CRAM-MD5.
Installation. CommuniGate Pro is available for a variety of platforms in addition to NT, including several UNIX variants, Apple MacOS X Server (aka Rhapsody), and Windows 9x. The software ran well on the Windows NT Magazine Lab's 256MB test server.
Installation isn't difficult. After you unzip the installation files, a README file guides you through the initial software installation. Installer.exe prompts you for two file paths, for CommuniGate Files and CommuniGate Pro Directory. Mailbox and queue files reside in CommuniGate Files, and program executables reside in CommuniGate Pro Directory. The installation process creates a Postmaster account that you use to set up accounts and configure the system. The system generates a random password for the Postmaster account. Rather than displaying the password, the installation instructions direct you to find the randomly generated password in a text file in the Accounts directory. If you choose to change the password to something easier to remember, you must restart CommuniGate Pro before configuring the system. CommuniGate Pro runs as one NT service, in contrast to the other mail servers I tested for this review, which installed multiple services.
Documentation. CommuniGate Pro's documentation is Web-based and contains clear descriptions of the various components of the product. However, during my testing I wished I'd had a PDF version of the manual, and a way to search the entire documentation set for keywords.
Configuration and management. CommuniGate Pro incorporates a Web server to support system administration and user-account management. Connecting to port 8010 brings up the system administration pages, which are logically organized into four groups: SETTINGS, Accounts, Domains, and MONITORS, as Screen 1 shows. To complete the basic configuration, I entered an email domain name and created mailbox accounts. If you convert from another mail system, CommuniGate Pro will use information in a tab-delimited file to create numerous mailboxes. With only a few minutes' effort, I used Microsoft Excel to make a tab-delimited file that created 1000 users.
The software's default tuning parameters are suitable for the typical loads that a small business generates. However, I planned to stress the server with a heavy load, so tuning was necessary. Because I planned to simulate up to 1000 concurrent users for benchmark testing, I configured 1000 SMTP receiving channels, 1000 POP3 channels, and 10 local delivery threads. The SMTP receiving channels support client connections sending mail to mailboxes in CommuniGate Pro. The POP3 channels support connections from POP3 mail clients. When the SMTP module receives a mail message, the module places the message in a delivery queue. The software hands off messages addressed to local users to a local delivery agent for delivery into a user's mailbox. The default number of local delivery threads (one) couldn't keep up with the rate at which the server received messages during heavy-load testing. With 10 delivery threads, local delivery of mail messages completed within 5 minutes after the end of the test.
POP, IMAP, and Web access. I used Outlook Express and Eudora Pro 1.0 to test CommuniGate Pro's POP3 and IMAP4 client support. Using both programs, I sent and received mail, created IMAP folders, and moved mail between folders.
The software's Web access was a pleasant surprise. Stalker fully integrated Web support into CommuniGate Pro, and the support doesn't require a separate Web server. Using Microsoft Internet Explorer (IE) 5.0, I sent and received mail, sent and saved attachments, created IMAP folders, and moved mail between folders. The Web client displays entire messages in one pane, and you can scroll the pane to view the entire message. You can move between unread mail items in a folder without having to return to the folder view. You can mark messages as read or unread, flag messages for attention, and undelete messages that you marked for deletion. The software also supports user Web pages when the mail administrator enables this feature for a mailbox account. Web access to email lets users access functions that aren't available through most POP3 or IMAP4 clients, including the ability to set an automatic reply message and to control the appearance of the mail viewing and composing screens.
List-server features. CommuniGate Pro includes a full-featured list server. The software supports moderated and unmoderated lists and lets you define who can subscribe to an unmoderated list. Users can select message delivery when the list receives the message, delivery of periodic message digests, or delivery only of the digest table of contents. Index subscribers can use the Web access facility to view messages. You can configure lists to accept messages from anyone, from list members only, or from users in the same mail domain. In addition to letting users send a subscribe email to the list, the mail administrator can import member addresses from a text file.
Performance. CommuniGate Pro performed well in my testing, delivering a third-place maximum throughput of 60.3tps in the benchmark test. Unfortunately, CommuniGate Pro also holds the distinction of exhibiting the worst drop in performance when the load increased beyond the point of best performance; the drop was such that the software couldn't successfully complete the last step of the test. I might have been able to cure this behavior with a little additional tuning, perhaps by specifying fewer threads in support of delivery of queued mail to local mailboxes, but I didn't have the time to test this theory. In CommuniGate Pro's favor, the software was the only product that let me configure local delivery threads. This capability lets mail administrators balance system resources that are dedicated to receiving mail for the queue with resources that deliver mail to a user's mailbox.
Final valuation. CommuniGate Pro is the most full-featured of the six mail servers I tested. The software comes with a good Web-based mail client, LDAP support, a full-featured list server, and plenty of performance and scalability. Mailbox for mailbox, of the six products I tested, only MailSite costs less than Communigate Pro, and MailSite lacks some of CommuniGate Pro's key features. CommuniGate Pro is a great value.
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