1. Never Allow All Routes to Users. You should always be able to limit the high prices of international to customers that need the service. It is not all the time that your customers will need the international termination. If you have a customer who wants the US-48 domestic termination, you should not give them the US-Extended coverage or the international dialing plans. You can only give customers who have requested for those destinations.
2. Block All Premium Rate Numbers. Make sure that you do not offer high-cost toll destinations to your customers. Blocking all premium-rate numbers is very essential and easy. Your customers should not be able to access such numbers unless they request you to give them.
3. Block Numbers Without A Defined Rate. As a company, you should make sure that you block all calls that you do not have a vendor cost. You should always block all numbers that do not have a defined rate. Many providers do usually do not offer such rates unless they get an underlying carrier invoice.
4. Limit Simultaneous Calls. Businesses should always be able to monitor and know the number of calls a customer can make at a given period. This will help you to set the maximum number of concurrent calls that your system can handle. A good way of knowing the number of calls made is by monitoring the average usage over a month or two. Make sure that you limit your equipment to the average number of calls. This will ensure that you eliminate call flooding.
5. Drop Calls. You should be able to drop calls after a certain period to reduce VoIP call damage. Make sure you set a maximum calling time, and this should go hand in hand with limiting the number of call channels. By doing this, you should be able to prevent fraudulent calls from lasting long hours and it will also help mitigate your exposure in such events. Limiting calling hours can also help reduce attacks. Make sure that you terminate fraudulent calls after an hour instead of a day.
6. Consider Using Geo-IP Restrictions. If you are not selling products in a particular country, it would be wise to block all IPs from those countries. This will help you minimize any fraud sources. You can simply block all fraudulent countries from receiving and sending traffic.
7. Use Prepaid Rather Than Postpaid Quotas. Always make sure that you set up a prepaid billing or postpaid quotas that will enable you to terminate unusual services in case of a break-in. If you block unproven post-pay calls, it will stop your customers from running large tabs. Those minutes can never be recovered once you allow them to be used.
8. Create an Alert System. Lastly, you should ensure that you build a system that is able to monitor all traffic and notify you if something is abnormal. The earlier you detect the breach, the sooner you can block and reduce the amount of money you will lose. If you have an automated report, you can easily detect unusual traffic and close them.