3CX Solves SIP/NAT Woes for SMBs

The maker of Windows-based PBX software provides a solution for getting VoIP calls through network firewalls.

By Adam Stone | Posted Feb 27, 2008
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As IP PBX maker 3CX continues to chip away at the small- and mid-size business market, the company is looking to overcome a common conundrum that plagues SIP-based VoIP implementations: firewalls—specifically firewalls that use Network Address Translation or NAT.

Here's a quick explanation: SIP, the increasingly ubiquitous Session Initiation Protocol, establishes a call between two endpoints—one outside the firewall, one inside—then turns over the responsibility for moving the voice packets to the Real-time Transport Protocol (RTP)—over a different port. NAT, however, in an attempt to keep traffic secure, steps in and changes port numbers, thus generally mangling connections.

(For a more complete explanation, read Getting SIP through Firewalls.)

So, as VoIP has begun to take hold outside of the enterprise realm, the difficulty of getting voice packets to reliably "traverse" NAT firewalls has also become an SMB concern. In its latest version, 3CX Phone System v5.1, the Cyprus-based company has incorporated new "tunneling" functionality to alleviate the problem.

"Even SMBs have firewalls. Once they install a router they are going to need to look at that aspect," said Nick Galea, 3CX's CEO. "We make that a lot easier with this tunneling."

Built on SIP, the 3CX Phone System works with virtually all SIP phones, SIP VoIP gateways and SIP VoIP providers. Its non-proprietary tunneling solution is likewise designed to function within SIP standards and accomplishes its purpose by channeling all VoIP traffic over a single port.

"With VoIP out of the box, working on SIP requires a lot of ports. It's a little bit chatty," Galea said. "What we have done is to bring it all down to one port, whilst maintaining our compatibility with the SIP standards."

Galea pitches the ease of use that he says in inherent in the 3CX tunnel. For example, firewalls can be configured to network via any port. Further, remote workers do not need to edit the firewall configuration in order to be able to reach the IP PBX from remote locations. Rather, the system administrator can define and manage a single configuration for all users.

The latest version of the 3CX system adds a number of other enhancements over prior iterations.

A new portal allows users to log in through any web browser and set extensions to transfer functionality from their office phone, capabilities such as voicemail and forwarding preferences. "You can do all these things from the web easily," Galea said. The system also incorporates a new fax via e-mail capability.

3CX Phone System for Windows is available in four editions: Free, Small Business, Pro, and Enterprise. While all versions support an unlimited number of extensions, the Free edition is limited to eight simultaneous calls. The Small Business also supports up to eight calls, while the Pro version can handle up to 16 and the Enterprise edition 32 simultaneous calls. Call capacity can be expanded with upgrade packs.

3CX is not the only tunneling solution on the market, nor is it the only IP PBX available. In positioning 3CX, Galea divides up the competition along several lines. First there is the hardware/software distinction. Then, among the pure software contestants, there is the Windows-versus-Linux divide. In that realm, he suggested, 3CX's decision to run with a Window-based product is helping to set it apart.

"A lot of people want Windows because that is what they already know how to use," he said. Among SMB users, "there is a substantial segment that sees it this way as well. They are warming to the idea of a phone system that integrates to their applications, and those applications run on Windows."

Just as Windows is helping 3CX approach the SMB market, the company's strategic alliances likewise have been crafted to appeal to small businesses.

Recently, for example, 3CX announced a deal with connectivity player Patton Electronics Company and connectivity software maker Deerfield.com to produce an SMB product bundle. The product rolls together such features as consolidated operations, computer-resident soft phones, and voicemail/email integration with 3CX's PBX solution.

Looking ahead, Galea said, 3CX will be seeking to boost user returns by developing tighter integration between its phone systems and such business applications as CRM and Outlook, "so that the phone ultimately can improve the productivity of the office worker."

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