const std::string::size_type per_pos = cidr_copy.rfind('/');
if ((per_pos == std::string::npos) || (per_pos == cidr_copy.length()-1)
|| (cidr_copy.find_first_not_of("0123456789", per_pos+1) != std::string::npos)
- || (cidr_copy.find_first_not_of("0123456789.:") < per_pos))
+ || (cidr_copy.find_first_not_of("0123456789abcdefABCDEF.:") < per_pos))
{
// The CIDR mask is invalid
return false;