I’m planning on doing more research on this in a while, but I should mention it now: the latest release of Stalker Software’s CommuniGate Pro email software includes basic VoIP support.
CommuniGate Pro (CGP) is kind of fascinating to me. At it’s heart, it’s just commercial email software. It does SMTP, POP, IMAP, LDAP, and web mail, all of which you can do for free with open-source software. However, if you’re a small business or ISP, and email means anything to you, and you aren’t tied to Exchange, you owe it to yourself to take a serious look at CGP. It’s fast, it’s reliable, it’s completely standards-based, it’s trivial to configure, and it’s cheap. It starts at $500 for 50 users and drops off quickly. For $2,000, you can get a 1,000 user license. Now ask yourself, how long would it take to set up a 1,000-user POP/Webmail/SMTP mail server? How much support time will it take?
I’m starting to sound like an ad. I’ll try to stop.
They also do clustered mail servers, but their previously-reasonable prices suddenly jump well into the 6-figure price range. This isn’t the way to go if you’re looking for SPOF-free corporate email for cheap.
Their more recent releases have added some Exchange-like functionality–they support MAPI- and web-based calendaring with an Outlook plugin (for an additional cost), and they’ll provide spam and virus filtering for a price.
The thing that’s always fascinated me about these guys is that they seem to be a dinky, 5-10 person outfit, but they’re able to keep adding features faster then anyone else on the market, and do it without turning their software into a complete pig. At Internap, we were amazed to discover that their basic server with SMTP, HTTP, POP, IMAP, LDAP, SSL for everything, decent logging, a web UI for configuration and for email, and a mailing list manager all fit into under 2 MB of RAM. Once it got running, with hundreds of busy users, it grew to need 15 MB or so, but that was about it. I think we only managed to crash it once or twice in two years, and that’s under a murderous load–I think I was averaging over 2,000 email messages/day for part of that, and I was rarely the busiest user. We had way more problems getting Linux to keep up with the server’s I/O load, but that’s a whole different issue–we were saturating 2 external RAID arrays for almost the entire day every day.
Anyway, the latest release (4.2) adds SIP and RADIUS to their list of supported protocols. It isn’t really intended for serious PBX-replacing VoIP, but rather for IM and voice messaging. Since Windows XP includes SIP IM software, this seems like a useful addition to CGP. It’ll do VoIP as well, but it’s based on email addresses, not phone numbers, so it’ll be hard to get SIP phones to interoperate with it (although not impossible–most of them will let you dial names, but it’s hard to enter them with a phone keypad).
Personally, I’m going to keep my eye on them over the next year or two–they aren’t very far from turning CGP into a cheap all-in-one solution for small-business communications. All they need is a dialing plan, voicemail, support for external SIP-to-PSTN devices, and maybe faxing.
One quick disclaimer–it’s been a couple years since I last used their software. I’m not a sysadmin at my present job, and I have nothing to do with out email environment. And, I’m not willing to pay $500 for my home email server, although I was tempted back in the .com days.