You probably have an idea by now how I don’t like Skype, well today I’ll go into some of the details as to why I don’t like it.

Skype is a peer to peer application and under some circumstances, the Skype client uses the specified bandwidth of between 24 and 128KbPS. If you have a high speed internet connection and your firewall is not very restrictive, your PC with Skype might become a “supernode”. In this mode, Skype starts to relay signaling for other Skype users that are behind NAT (network address translation).

You can test this behavior. Run a packet capture on your network before installing Skype, then capture packets after installing Skype. You’ll notice that if you are directly on a publicly routable IP address, your machine starts using a lot (if not all) of your available bandwidth. You’ll notice traffic going out to all sorts of addresses around the globe.

The bandwidth usage can be so considerable that in certain circumstances it has brought down Linksys routers (typically used as residential gateways).

Skype uses both TCP and UDP ports for this traffic and in tests can use up all bandwidth in a 100MbPS connection. Now think about multiple users running Skype (not even using it) at the same time.

So until Skype starts to ship with some sort of a management tool to enterprise to limit this “supernode” mode, I will not recommend anyone use Skype, besides it’s not like it’s free. Why would you want to use Skype when you can use other VoIP services for free!

Why would people want VoIP client on a handheld that is already a cell phone? VoIP clients can provide additional enhanced services specific to your organization, lower your per call costs and even provide you with unlimited minutes as long as you have unlimited internet access.

You know I don’t like Skype much, but it has to get it’s due. Skype has a version for Windows PocketPC that works on Windows Mobile. You can download the software for free from here.

Wifive323 is another soft phone for Windows Mobile. Wifive323 is available for download for free but the free version has an annoying beep every 10 seconds. Wifive323 can be downloaded from here.

SJPhone is available for PC or for mobile devices. This means if you use the same client on your PC and your handheld, you won’t need to learn a new interface. SJPhone can be downloaded from here.

Before you go about installing any of these clients, be sure your handheld has enough processing power.

If you’ve worked with VoIP, then you already know the tremendous savings you can enjoy. There are numerous companies, campuses and organizations that have enjoyed tremendous cost savings, boost in productivity and even entered new markets because of this technology.

A huge cost saving and productivity boost can be gained by integrating your CRM system with your phone system. This is especially true, if not a requirement for any call center. Now you can automate processes that you had to perform manually and eliminate procedures that were prone to human error. For example, a customer calls in to a call center, the customer caller ID is logged and matched up with CRM system that automatically pulls up account information. The call center agent types in the details of the call without having to hunt for customer specific information as it’s already on the screen.

Think about the up-sell potential if you can see past order history immediately as you pickup a call from a customer, you can also convert disgruntled customers to loyal ones by taking care of issues they’ve called about in the past. A simple thing like wishing someone a happy birthday can go a long way, only if your phone system is integrated with your CRM system.

Almost all VoIP phone system allow simple integration with CRM systems. These phone systems make calls to the CRM system via simple URL requests, which means integration is easy and you can connect with almost any modern  CRM system. Saleforce.com even allows integration with Skype!

There are many threats to a VoIP system and the list is only going to get bigger. Here’s a list of threats that will be most common in 2008 according to Sachin Joglekar, vulnerability research lead at Sipera Labs.

Remove Eavesdropping:
This is most common on VoIP systems that do not take into account security such as encryption. On a traditional phone system, someone will have to physically tap into a phone line to eavesdrop, on a VoIP system this is much easier if calls are not encrypted as all you need is a data feed. This data feed could be tapped into without physically connecting a hard wire to the network cable.

VoIP Hopping:
VoIP hopping can allow remote eavesdropping. VoIP hopping can allow a PC to mimic a phone and giving hackers a doorway to eavesdrop.

Vishing:
Similar to Phishing, Vishing allows scammers to change call parameters like caller id and present a fraudulent identity. A typical spam might lead people to believe they are talking to a rep from their bank and may reveal confidential information.

VoIP Spam:
Similar to email spam this represent not only junk phone calls but also more wasted time for people as they have to stop what they are doing to take the call and can fill up voicemail boxes.

Toll Fraud:
Toll fraud has recently been talked about a lot. A typical scenario of toll fraud is a case where hackers broke into a VoIP networks and “sold” long distance minutes to millions of unsuspecting people. Make sure encryption and analysis systems are in place in your VoIP deployment.

Skype Worm:
The popularity of Skype will prompt more and more worms being released that replicate through the network. One such worm was the W32.Ramex.A virus that replicated through instant messaging.

VoIP over WiFi:
VoIP by itself is insecure, if you decide to put it over WiFi make sure your WiFi network is secure or you will leave a huge surface area for an attack.

Weak Default Settings:
As with any system, you should not leave it at the defaults. Always change settings and shut down services you will not be using. A simple thing, but I’ve seen even default passwords on production systems.

Normally you won’t see me writing a lot about Mac, but after seeing user response looking for software for Mac, I decided I would make a list of what options Mac users have. Remember new Mac OS is basically BSD, so I think most Linux software should run with little to no modification.

Gizmo
Gizmo Project uses your internet connection (broadband or dial-up) to make calls to other computers. With the click of a mouse, you’re connected to friends, family, and colleagues anywhere on earth. It’s just that simple. You talk clearly. For as long as you want. For free.
And with inexpensive add-ons like CallIn and CallOut, you can talk to any telephone, mobile or landline, on the planet.

• License: Freeware
• Author/Publisher: SIPphone
• Requirements: Mac OS X 10.3.9 or higher

Download File Size: 18.6 MB
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LoudHush
LoudHush functions as an IAX client for the Asterisk PBX. With LoudHush you can initiate and answer, hold and transfer voice calls using your computer.

• License: Shareware
• Author/Publisher: LoudHush
• Requirements: Mac OS X 10.3 or higher

Download File Size: 1.6 MB
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ohphoneX
ohphoneX (pronounced as “oh-fone-ten”) is a H.323-compliant client application for video conferencing and IP telephony. It uses the protocol stack developed by the OpenH323 Project. ohphoneX is the first application from the XMeeting Project, the goal is to bring standard based video conferencing and IP telephony application to Mac OS X. ohphoneX is designed to be a simple application that does Mac-to-Mac and Mac-to-PC (i.e. NetMeeting) audio/video conferencing, as well as Mac-to-Phone voice only communication. Therefore, advanced features such as multi-party conferencing and answer machine is not included in this release. However, these features will be included in other applications from the XMeeting project.

• License: Freeware
• Author/Publisher: XMeeting Project
• Requirements: Mac OS X 10.2.4 or higher

Download File Size: 4.4 MB
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SJPhone
SJphone is a SIP/H.323-based softphone for Mac OS X, MS Windows, Windows CE, Linux and other VOIP applications. A number of advanced features make it possible to meet the needs of both personal users and service providers.

• License: Freeware
• Author/Publisher: SJ Labs
• Requirements: Mac OS X

Download File Size: 4.7 MB
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Skype
Skype is the next phenomenon from the people who brought you KaZaA. Just like KaZaA, Skype uses P2P (peer-to-peer) technology to connect you to other users - not to share files this time, but to talk and chat with your friends.
Our software’s quick and easy to install. Just download Skype, register and within minutes you can plug in your headset, speakers or USB phone and call your friends. The calls have excellent sound quality and are highly secure with end-to-end encryption. You don’t even need to reconfigure your firewall or router. It just, you know… works.
You can also use our SkypeOut function to make calls to friends who only have a landline or mobile phone anywhere in the world at local rates. You can even transfer files of up to 2 gigabytes. *Remember Skype uses proprietary technology compared to most other softphones listed.

• License: Freeware/Paid service
• Author/Publisher: Skype Technologies S.A.
• Requirements: Mac OS X 10.3.9 or higher

Download File Size: 30.8 MB version 2.6.0.184 for Mac OS X 10.3.9 to 10.4.11
Download File Size: 34.4 MB version 2.7.0.195b for Mac OS X 10.3.9 to 10.5.x - November 29, 2007
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TeamSpeex
TeamSpeak is a Voice over IP program used by alot of gamers to communicate with each other with voice. The TeamSpeak client is available for Windows and Linux users and an official Mac client has been announced more than 1 year ago but there is still no Mac client as of today..
So I was tired of waiting and seeing Mac users being left in the dark and not supported by not having a client, up until now ofcourse because (you probably already guessed it) TeamSpeex is a TeamSpeak client for Mac OS X!
I named it TeamSpeex because it only supports the Speex codec. It is fully compatible with existing TeamSpeak servers, and with PC and Linux users.
TeamSpeex is a third-party client for TeamSpeak, that means they have nothing to do with this product. So do not bug or contact the TeamSpeak developers if you have problems related with TeamSpeex.

• License: Freeware
• Author/Publisher: TeamSpeex
• Requirements: Mac OS X 10.4 or higher

Download File Size: 902 Kb
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Ventrilo
Ventrilo is comprised of two primary Components: The Client that every end user will need to download, and the Server. Only one person needs to host a Server that all of the other Clients will connect to. Ventrilo is supported on different platforms as well ranging from Microsoft Windows to Apple Manintosh and Linux.

• License: Freeware
• Author/Publisher: Flagship Industries
• Requirements: Mac OS X 10.3 or higher

Download File Size: 4.6 MB
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X-Lite
CounterPath’s X-Lite 3.0 is the market’s leading free SIP based softphone available for download. Based on the advanced architecture of eyeBeam 1.5 (CounterPath’s carrier grade telephony client), the new X-Lite is designed to showcase some of the feature rich capabilities available with our commercial softphone such as superior audio and video quality, zero-touch configuration, IM & Presence, and a comprehensive personal address book.

• License: Freeware
• Author/Publisher: CounterPath
• Requirements: Mac OS X 10.4 or higher

Download File Size: 14.6 MB
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XMeeting
With each release, XMeeting is becoming more and more stable, compatible and usable. Starting with the release of version 0.2, XMeeting has almost all features included with ohphoneX and already has many important new features that ohphoneX never had. And, XMeeting simply looks better! If you’re using Mac OS X 10.4 “Tiger”, we recommend you to start using XMeeting for video conferences. We’re still working hard on improving XMeeting and adding many important videoconferencing features.

• License: Freeware
• Author/Publisher: XMeeting Project
• Requirements: Mac OS X 10.4 or higher

Download File Size: 8.6 MB
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Zfone beta
I think it’s better than the other approaches to secure VoIP, because it achieves security without reliance on a PKI, key certification, trust models, certificate authorities, or key management complexity that bedevils the email encryption world. It also does not rely on SIP signaling for the key management, and in fact does not rely on any servers at all. It performs its key agreements and key management in a purely peer-to-peer manner over the RTP packet stream. It interoperates with any standard SIP phone, but naturally only encrypts the call if you are calling another Zfone client. This new protocol has been submitted to the IETF as a proposal for a public standard, to enable interoperability of SIP endpoints from different vendors.
Zfone has been tested with these VoIP clients and VoIP services:
VoIP clients: X-Lite, Gizmo, and SJphone.
VoIP service providers: Free World Dialup, iptel.org, and SIPphone.

• License: Freeware
• Author/Publisher: Philip Zimmermann
• Requirements: Mac OS X 10.4 or higher

Download File Size: 379 Kb
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There is no such thing as free VoIP calls if you intend to call regular telephone lines. Some services come close and if you are ok with calling other computers only there are some free services.

Most services that tout to be free when calling land-lines, in fact require a deposit or have trial period limitations. Some services give you certain amount of time free, and then start charging when you exceed the threshold, so pay attention to how much time you are using with such services.

If you are only calling another computer, then why even bother with services such as Skype and their Suprenode issues? Simply use Google Talk or MSN/Windows Messenger! Google Talk has a nice web interface not requiring software installation on your machine, great way to VoIP enable any PC.