We had two reports recently that customers lost money from their SIM cards connected with our service on public IPs. Further investigation of one case showed that customer was using simple passwords on the devices. In device security settings they also had no any restriction for incoming calls from internet. With this scenario, anyone who scans IPs will get a reply on some VoIP port and http port from the device. After that they can try to send call there or guess the password and login to web interface to check device settings and allow calls from anywhere, so they could send calls then. To avoid such cases please do the following:

  • use secure password for your device;
  • restrict calls to accept them only from your SIP trunk IP or VoIP switch IP;
  • in case you can’t restrict calls by IP, choose our bandwidth optimization service and ask to set your devices on private IP range. You will still be able to access devices remotely by accessing your Linux PC desktop with VNC or similar program and then accessing your devices from there.

Performing these simple steps will avoid money loss on your GSM/PSTN carriers.

Please note that VPN with public IP considers that anyone from internet can access your IP. Many special programs do automated port scans over internet to gather information about IP address. Please consider your security and never use easy to guess passwords on any services that you put on public IP. Also check security settings and hide everything that you don’t wish to be available publicly.