LJ Archive

CommuniGate Pro Mail Server

Scott Wegener

Issue #70, February 2000

Stalker Software has received numerous awards for their CGP product.

  • Manufacturer: Stalker Software

  • E-mail: James_Bond@stalker.com

  • URL: http://www.stalker.com/

  • Price: $499 for 50 users

  • Reviewer: Scott Wegener

With the Internet continuing to grow by leaps and bounds and more people becoming exposed to it, a proliferation of new network and Internet-specific software is coming out, giving potential buyers a confusing array of software from which to choose. Free web hosting and “free e-mail for life” sites now number in the hundreds at least, and seem to be multiplying daily. Most companies now require Internet access, including at least a corporate web site and employee e-mail. Many sites are either running NT and the Microsoft Solution for mail and web services, or using UNIX systems such as Sendmail along with a POP3 or IMAP server. After all, Sendmail has been with us for ages, and it's something most UNIX administrators are familiar with. MS Exchange and Sendmail pretty much dominate most mail-server markets today, so why change? Stalker Software (http://www.stalker.com/), a company with a background in Macintoshes and mail software, intends to change all that with their CommuniGate Pro (CGP) mail server.

While Stalker appears to have their work cut out for them, they are also off to a good start. The company has received numerous awards for the CGP product, ranging from UNIX Review to the Linux World Editor's Choice. Not being content to blindly listen to others' reviews, I sat down to install CGP on my mail server running Red Hat 6.0. If you don't use UNIX for your mail server, they've got you covered there as well. CGP runs on a broad range of platforms, including most UNIX variants, Mac OS X Server and Windows, and is currently in version 3.1 as of this writing, with a 3.2 beta available for testing.

Installation, Configuration and Administration

Installation is fairly straightforward for all versions I've tested, those being Red Hat 5.2 and 6.0 (RPM and tgz) and Windows NT 4 Server. For review purposes, I'll be concentrating on the Linux version, although everything aside from the installation itself should apply across all platforms. The install script adds its init scripts for startup and shutdown, replaces the mail binary with a CGP-compatible version, and you're off and running. We're not done yet, though. Stalker realizes many users will be migrating from another system, such as an IMAP or POP server. CGP/Stalker provides some simple tools to import users and mailboxes, which can mean the difference between a relatively quick and easy installation, or an all-day (or longer) process for companies with hundreds or thousands of users. You can, of course, also add users manually. Users can even be imported/created via a simple text file, which can easily be made from your password file.

Once the server is up and running, administration is normally handled via a web interface. For the more security-conscious, a nice feature is that with versions 3.1 and later, this can be done via an SSL web connection. For the truly stubborn, it can also be configured via text files. While I am not a fan of web interfaces, this one is quite good. On-line HTML help is part of the system and just a click away. Earlier versions had pointed to the Stalker web site, but now all documentation is available locally. Mail domains and routing, access rules, log levels and all configuration is easily done. It does take a while to become used to getting around the interface the way it's laid out, as well as learn some of their terms, so the help does come in handy for the more unusual features.

Features, Features, Features

After the initial configuration is done, you have a large number of choices to make. For the most part, the defaults may be acceptable and are enough to get the system up and running, but the fact that this is certainly no trimmed-down mail server becomes readily apparent once you spend some time in the Admin screen. You have quite a few options, such as allowing web-based mail access, using SSL, allowing IMAP, POP, ACAP and PWD clients, maximum number of connections allowed, log rotation and levels, mailing-list configuration, blacklisted domains and more. Most of these will already be familiar to mail administrators, and others may be new to some. Administrators may also limit system resources, message size, allowable services, and web space on a per user/list or per domain basis, as well as setting new defaults.

A very nice feature is server-wide rules, which allow us to bid adieu to fighting with procmail recipes. Or perhaps not—the rules also allow the execution of external scripts, if you so choose. They allow anything from simple redirections to auto-replies using the sender's information inside of the reply message.

An LDAP module is included as part of CGP. CGP also provides its own web server module, allowing users to create their own web sites and update them via the Web Mail interface. The list goes on and on—after using CGP for several months, I'm sure there are yet more pleasant surprises to be discovered.


One of the nicer features about CGP is the ability to customize. You decide which services you want to provide or allow, based on per domain or per user. You could allow only secure connections, or restrict connections via IP or domain. And the web interface, including the web actions dictated by each link, may be customized to suit your taste. The default Web Mail configuration is acceptable for most intranets, but ISPs and free e-mail sites would certainly want to add their own layouts. This seems to be easily accomplished, based on feedback I've seen on the CGP mailing list, including the use of custom CGI scripts, or choosing from ones available on the Stalker web site. Future upgrades will leave your changes intact, but use common sense; always make a backup.

The Web Interface

It's inevitable—everyone has seen it. Most of us have one somewhere or another. Some people love it, some hate it—web mail is here to stay, and can make life much easier for those on the road or otherwise remotely accessing e-mail. The default web mail configuration is usable, but has some quirks and annoyances. To be fair here, so do Yahoo, Hotmail and the like. The web interface can be customized almost to your heart's content, and it does provide some nice features. I have not done any customization, but several commercial customers on the CGP list seem to have had success with it. Therefore, any comments here are about the default interface only.

Users are able to configure their web-mail settings to include sort order, number of messages to display per screen, which mailboxes to display, signature and reply formats and too many other things to cover here, but suffice to say it's quite nice. Users also have the option of polling external mailboxes via POP3, and as an added bonus, can use the web interface to upload and maintain their personal web site. A user may also define his own rules, using the same options as the server-wide rules—an option any user subscribed to mailing lists will definitely appreciate.

All is not perfection, however; a few annoyances remain, most notably the default “Delete” and “Next Unread” operations. Upon deleting a viewed message, a user is brought back to the Mailbox, rather than the more usual behavior of moving on to the next unread message without requiring user intervention. The “Next Unread” seems to ignore any sort order a user has specified and moves on to the next unread message in its mail file rather than using the sort order for displaying messages. This may sound minor, but it can be quite frustrating with a folder containing a lot of unread messages. The Delete behavior can (thankfully) be fixed easily by making a minor change to the HTML.

The last remaining quirk relates to the way some mail clients send web pages as attachments. Under some circumstances, the user is confronted with a message about “Embedded Web Pages” and his browser being unable to display in-line frames. So far, Netscape Messenger and Outlook Express produce the same result. When this happens, the user must click on a link to launch another browser window in order to view it. Hopefully, this will be fixed shortly.

Users, Lists and Normal Operations

I've used everything from Pine to Netscape and Outlook to retrieve mail from CGP and have yet to run into a problem using these clients via IMAP or POP3. Mailing lists are easy to set up, and also allow accessing them via the Web. They can be configured to automatically digest and support the typical features under traditional list servers such as majordomo, allowing for both moderated and unmoderated, public and private lists. The help files, list notifications and bounce processing are easily configured and customizable.

The Good

  • easy installation & administration

  • many tools and features

  • highly customizable

  • thorough administration package

  • mail transport agent and web e-mail service

  • retrieves POP3 or IMAP

The Bad

  • next unread operation is disorganized

  • delete operation exits folder

  • web page attachments are problematic

Day-to-day administration is minimal, since the log rotation and most tasks are handled for you (once configured). A note of caution is in order, however; the logs can get quite large if all data is being logged, so after determining the server is in working order, logging policies should probably be altered. A “Monitors” section of the Admin interface allows you to watch all active connections via the Web and other protocols and view any logs, including filtered logging by content or time. One minor complaint is the log is displayed in reverse order with the most recent events displayed at the bottom of the page, which may be off the screen. A nice addition would be to send a notification if more connections are being requested than are configured, to enable system administrators to determine more easily when they may need to allow more connections or upgrade hardware. Aside from that, most administrators should rarely need to use the monitors section as the system practically runs itself, but it's good to know it's there.

Target Audience

With the abundance of features packed into CGP, it may sound a bit overwhelming to some system administrators at first, but let me assure you this is most certainly not the case. Most features are easily configured, and if you don't need a particular service, don't run it. Click a checkbox and it's off—it's that simple. The Web Mail interface obviously targets free e-mail services akin to Yahoo! and Hotmail, but it is much more than just Web Mail and should be equally at home in small companies, ISPs or large enterprise networks. For those interested in using it as a free web mail server, header and trailer fields are allowed to be set. I've seen people quote anywhere from a dozen to over 100,000 users on the mailing list so far, and just in case you want to support more users, CGP also has a “Cluster” option that allows you to use multiple servers in tandem.

Customer Feedback—Some First-Hand Comments

Software evaluations and reviews often leave out an important part—real-world use. A quick e-mail to the mailing list yielded several responses from different companies currently using CGP, ranging from a school with 1200 or so accounts to several companies using the web interfaces for free e-mail services supporting tens of thousands of users.

Ofer Tanenbaum of Zipmail (http://www.zipmail.com/), which offers a free web-based e-mail service, says Zipmail already has over 20,000 users and is growing daily, running on an Intel-based FreeBSD server with less than .07 CPU load and over 100 concurrent connections. Zipmail had tried EIMS and Appleshare IP previously, and Tanenbaum had some personal experience with MS Exchange. His overall impression? “Bottom line, nothing to compare.”

MauiMail (http://www.MauiMail.com/) is also using CGP for web-based e-mail and has been running CGP for about a year, on an Apple G3/450. An employee of MauiMail, Darly Hansen, claims it to be “much smoother than our previous system. Very stable.” Most other responses I've gotten from the list tend to agree.

Pricing and Support

Pricing is free for a trial version and starts at $499 to license 50 users, 1000 accounts at $1999, on up to $30,000 for unlimited accounts and lists. Support packages vary, but free support via e-mail is included, with additional packages ranging from five incidents through unlimited 24x7 with guaranteed on-site support at varying costs. I've monitored the mailing list for several months, and for the most part problems are answered the same day, sometimes within hours, including on weekends.

Some of the list members have been doing heavy customization to the system, mainly the Web Mail configuration. While not always able to resolve an issue immediately or the first time in some cases, there almost always seems to be a way to do what the customer wants.

The documentation does a good job as well, but can be a bit overwhelming in size. On-line help is available to the administrator and users alike through the web interface. The list also serves as a place to make feature requests, and staff members at Stalker are very motivated to keep their customers happy.


Many products in the past have tried to be all things to all people, ranging from Windows and all its permutations to the different groups working on making Linux alternately either a desktop OS or a server OS. Most have mixed results, giving up something in trying to be too many things. Surprisingly, this is not the case with CommuniGate Pro. With its abundance of features and ease of administration, it practically runs itself once configured and is up to any task you may ask of it. If you need a feature, chances are there's already a way to do it, or it's coming soon. So, is it perfect? No. However, while it could use a few tweaks here and there, most are minor, which is all the more impressive considering the scope of the product. So who needs Exchange or cryptic Sendmail and procmail configuration? Not me, I'll take my CommuniGate Pro!

Scott Wegener started programming in BASIC on a TRS-80 CoCo way back when, and has been using Linux since before it came on CDs. He is currently employed as a software engineer and sometime system administrator by VERITAS Software, where he develops cross-platform reusable components. He can be reached at wegster@mindcore.net.

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