As an engineer for RingCentral I can tell you with authority we are definately not doing this to rack up minutes. This is actually a result of malicious intent. "Hackers" use a program calle SIP vicious to probe peoples networks and compromise phones. They then attack your phones by ringing them and ultimately get your login information from your phone. They can then use your specific login information to login to the RingCentral and make calls on your behalf. You can validate one of these attacks if your phone rings with a suspicious caller ID ("100") and then if you look in your RingCentral call log it will not show the call. That means the call didn't come through RingCentral servers, and the attackers have found a way in to your network. This can be mitigated one of 2 ways.
1. Recommended that you limit traffic to and from your phones ONLY from RingCentral IP addresses. You may need to enage the help of an IT professional to do this. The IP ranges you should be accepting traffic from are 199.255.120.0/22 and 199.68.212.0/22
2. To help with this issue RingCentral has recently implemented encrypted SIP registration or SIP TLS. This encrypts all communications back and fourth between RingCentral and your phone. This eliminates the ability for anyone on the internet to be able to just log in to your phone. You can ask to have this enabled by calling in to RingCentral support and asking them to enable this feature. Note: This conversation was created from a reply on: Why am I receiving calls from no one?.
1. Recommended that you limit traffic to and from your phones ONLY from RingCentral IP addresses. You may need to enage the help of an IT professional to do this. The IP ranges you should be accepting traffic from are 199.255.120.0/22 and 199.68.212.0/22
2. To help with this issue RingCentral has recently implemented encrypted SIP registration or SIP TLS. This encrypts all communications back and fourth between RingCentral and your phone. This eliminates the ability for anyone on the internet to be able to just log in to your phone. You can ask to have this enabled by calling in to RingCentral support and asking them to enable this feature. Note: This conversation was created from a reply on: Why am I receiving calls from no one?.
