SPIT (spam over internet telephony) has increased suddenly with a great frequency that you now hear unwanted phone advertising messages. Email spamming was one major issue which has been brought down somehow and now we have SPIT. The result of spam was so much that most of the people stopped opening there mailbox itself. We really don't want to repeat our mistakes? Nevertheless, SPIT is still not that great problem as of now and most experts believe it might just do so as more and more people are VoIP'ing around the world and this looks to be the future market attraction point.

Let's take a look how SPIT actually works. Unlike landline, the VoIP line is not just a telephone number, but is also an IP address. Unlike Auto dialer whom a tradition advertiser would use to dial each number one after the other separately, SPIT is way different, VoIP spammer can do things in much more efficient way. Get a load of IP addresses and send the recorded advertisement to those IP address at the same time cause thousand of VoIP call generation repeating same message a number of times. These messages can straight go into Voice Mailbox and can be heard at user's convenience. Now this is just like EMAIL SPAMMING.

Not only that, its pretty difficult to trace a VoIP call origination as compared to standard PSTN (public switched telephone network) calls and so these spammers are real fox to catch. With such facility like VoIP, a call can be made form anywhere at cheaper rated as compared to landline rates.

So where is the misuse of VoIP?

• SPIT can cause advertisements to flood a voice mailbox leaving no space for legitimate user's voice message causing a voice mail denial of service (DoS).
• An audio message takes more space than a text message and tones of such audio messages can pile up a voice mailbox space quickly causing the server hosting that mailbox to heat up with such pressure.
• SPIT doesn't restrict its boundaries to recorded calls but it can very well be a live call as well. Majority of people would tend to get carried away if they hear a call coming all the way from a bank or credit card company.
• Based on called ID, you may choose not to pick a particular call, but in many ways a called ID can be spoofed showing up a different number encouraging a user to answer the call.

What can be done?

There are companies like Qovia and BordeWave working on some of the VoIP spam control filters as according to them, just like email span, VoIP spam is subject to a specific pattern which is going to be filtered out along with blacklisting of such number and IP addresses recognized for VoIP misuse. Next time they try to do any such act, they are most likely to get blocked at the SIP-aware proxies and firewalls specially designed to prevent SPIT and to protect VoIP calls, caller ID spoofing, and other VoIP abuses.