Domain name system (DNS) servers provide Internet protocol (IP) addresses that computers must have for finding websites on the Internet. A recent problem with navigating the Internet is that hackers have discovered ways to change the IP addresses stored on the DNS servers. An altered IP address will cause an Internet user to be directed to an incorrect or fraudulent website. In the present invention, an Internet user's computer stores domain names and corresponding IP addresses of all websites visited with the computer. Each time a website is accessed, the IP address received from the DNS server is compared to the IP address stored in the database. If the IP addresses are identical, then the newly received IP address is likely legitimate. If the IP addresses are different, then the newly received IP address is likely fraudulent, and the user can be warned before loading the website.