Why has this happened? The internet has brought cost savings to every type of communication it touches. VoIP brings the same level of cost saving as email has to written communication and with that gain unsolicited advertising calls will soon follow.
Until SIP, many VoIP system were inoperable. That is changing and with thousands of SIP enabled PBXs connecting to the internet SPIT will soon start to invade your customers. SPIT and fraud will increase until the industry understands the security issues, just as they have with previous technologies.”
As usual someone has the answer. There are a number of rules according to Lynch;
1. Don’t leave your PBX open to the internet (only your SIP service provider).
2. Point Enum at your SIP provider. They can deal with SPIT better than you can.
3. If very concerned, use a voice only DSL like VxDSL.
These rules will help initially. Over time the SPITers will become more and more sophisticated, just like the spammers. There is one problem with this, spam filters get to read the email before it’s delivered. With a voice call, the SPIT filter can’t tell what the caller is going to say. Blacklisted IP addresses will stop some SPIT calls but internet based calls may need to go through simple IVRs, such as “Please press 29# to be connected”.
Using a voice only DSL service will significantly reduce your threat of SPIT. These services do not use the internet and may come with a managed router which controls access to your PBX. So your switch isn’t vulnerable to the same risks as having it directly connected to the internet.
Luckily, there are a number of projects developing ways to stop SPIT even before it starts to hinder users. Your SIP provider will just become your anti-SPIT provider.