Many phones support Direct IP calls allowing one VoIP phone to call another VoIP phone by dialling the destination phone's IP address, without using a service like sipgate.
Unwanted or nuisance Direct IP Calls are called SPIT calls (Spam over Internet Telephony).
These calls aren't being made to your sipgate phone number or routing over our network. You will need to review your local network and VoIP phone configuration to block these types of calls.
As a local network and phone security issue, the best support and assistance will be provided by your local IT administrator with support from your VoIP device and/or router manufacturer's support teams.
Using a Local or Listen SIP Port value other than the default port value 5060 should put an end to these types of calls. While this may stop these calls, this step alone is not a solution.
Most recent VoIP phones will have an option to disable Direct IP Calls. Most quality VoIP phones and devices will also have other settings that can be used to block these SPIT calls:
The available options will vary depending on the model of your phone.
- Most Grandstreams will have an option to "Disable Direct IP Calls" (under Settings -> Advanced Settings).
- Under Profile/Account set 'Check SIP User ID for incoming INVITE:' to 'YES'. Otherwise please open Account x -> SIP Settings -> Security Settings and look for the option 'Accept Incoming SIP from Proxy Only'. Please set this to Yes.
(Firmware Version v8)
Under Advanced -> QoS/Security, set the option "Filter packets from Registrar" to Yes.
Your router should also have a wide range of security options. You should contact your router manufacturer's support for advice and recommendations.
At the very minimum as an initial step, please change your sipgate login and SIP Password, change the Administrator passwords and update the firmware used by your VoIP phones, routers, and other networked devices as well as scanning your computers, smartphones, etc for viruses and malware.
If your router firewall supports the option, you could limit VoIP traffic to our IP ranges:
Ultimately, your local network's configuration and its security is your responsibility and outside sipgate's scope of support.
If you're receiving SPIT Calls, the best source of help will be provided by your VoIP phone and/or router manufacturer's support staff.