invalid IP addresses are marked as valid in the is_public_ip_address

in the is_public_ip_address subroutine in utils.pm, the code first checks whether the IP address is valid. If the address is invalid, the subroutine should return 0 (i.e. the address is NOT a public IP address); instead it returns 1, and in some cases, this can result in an invalid IP address being set as the computer's public IP address.