May 19, 2011, 2:09 PM — While many people use Skype for its free voice over IP (VoIP) services, Linux users have a love/hate relationship with it. Yes, Skype will run on some versions of Linux, but it doesn't run on all of them, and the Linux version (2.2-beta) lags far behind the Windows version (Skype 5.3). That's three major generations behind. Need I say more?
Much as I dislike Microsoft's recent purchase of Skype and even though I think Skype's technology is held together by bailing wire and duct tape, maybe Skype will become better for Linux with Microsoft. After all, it couldn't be much worse!
That said, there are numerous Linux VoIP programs and they're also free as in "free beer," as well as free as in "free software." Most of these programs use the open SIP (Session Initiation Protocol) standard or Extensible Messaging and Presence Protocol (XMPP) If they use the same protocol, you should be able to use one client to call another. To do this, of course, they must be on the same SIP or XMPP network. For example, I use the Ekiga.net VoIP network for SIP calls.
None of them, however, can work natively with Skype. Skype is a proprietary system and locks users into using it. You can set Skype up with Skype Connect to work with SIP VoIP systems, but this is a paid service. There are efforts afoot, such as the karaka Google Project to create Skype/XMPP gateways, but they're for developers, not ordinary users.
There are also numerous Linux based IM clients, such as Pidgin, that also include some VoIP support.
The Linux VoIP clients also have some other things in common. On the down side, none of them allow desktop sharing. That's not a feature I use very often, but it's one that's used all the time in technical support operations. In addition, except for the Google family of voice applications, none of them make calling from VoIP clients to phone company telephones easy.
So, that said, let's take a brief survey of Linux's Skype alternatives.