Private IPv4 Addresses

ipv4-private.js

// This pattern matches IPv4 private IP ranges, plus loopback address. 
//
// Pattern 1 matches the beginning of the IP address only, so it cannot be used
// in situations where the entire matched IP address is required.
//
// Pattern 2 returns the entire matched IP address.
//
// @see https://en.wikipedia.org/wiki/IP_address#IPv4_private_addresses
var pattern1 = /^(127\.0\.0\.1)|(10\.)|(192\.168)|(172\.(1[6-9]|2[0-9]|3[0-1])\.)/g,
    pattern2 = /^(127\.0\.0\.1)|(10\.\d+\.\d+\.\d+)|(192\.168\.\d+\.\d+)|(172\.(1[6-9]|2[0-9]|3[0-1])\.\d+\.\d+)/g;