Consumer-grade internet routers can sometimes obtain a new public IP address on demand from the internet service provider using DHCP lease renewal to circumvent individual IP address blocks, but this can be countered by blocking the range of IP addresses from which the internet service provider is assigning new IP addresses, which is usually a shared IP address prefix. However, this may impact legitimate users from the same internet service provider who have IP addresses in the same range, which inadvertently creates a denial-of-service attack.