How to see if an IP address belongs inside of a ra

Question

Here I have a static reference the ranges I need to check:

private static List<string> Ip_Range = new List<string>()
{
    "12.144.86.0/23",
    "31.201.1.176/30",
    "46.36.198.101/32",
    "46.36.198.102/31",
    "46.36.198.104/31",
    "46.136.172.0/24",
    "63.65.11.0/24",
    "63.65.12.0/25",
    "63.65.12.128/26",
    "63.65.12.192/27",
    "63.65.12.224/28",
    "63.65.12.240/29",
    "63.65.12.248/30",
    "63.65.12.252/31",
    "63.65.12.254/32",
    "65.173.56.0/21",
    "67.23.241.179/32",
    "67.23.241.180/30",
    "67.23.241.184/29",
    "67.23.241.192/30",
    "67.23.241.196/31",
    "67.23.241.198/32",
    "72.32.164.56/29",
    "72.46.244.32/28",
    "74.91.16.48/29",
    "74.91.16.208/29",
    "74.91.20.48/28",
    "74.91.20.64/29",
    "74.112.134.120/29",
    "74.112.135.104/29",
    "74.205.37.16/29",
    "78.24.205.32/28",
    "98.129.27.88/29",
    "98.129.91.40/29",
    "166.114.0.0/16",
    "167.157.0.0/16",
    "174.143.165.80/29",
    "186.0.156.0/22",
    "186.2.0.0/17",
    "186.27.0.0/17",
    "190.0.248.0/21",
    "190.3.184.0/21"
};

Here's some pseudo code on how I see it working:

public static bool IpIsWithinRange(string ip) //Something like 127.0.0.1 or 184.56.26.35
{
    IPAddress incomingIp = IPAddress.Parse(ip);
    foreach (var subnet in Ip_Range)
    {
        IPAddress sub = IPAddress.Parse(subnet); ?????
        if (incomingIp "is in" sub) ?
            return true;            
    }
    return false;
}

Any suggestions on how to code up this functionality?

Answer 1

I use the below method to determine whether a given IP Address is a public one or private/internal:

private bool IsInternalIpAddress(string ipAddress)
    {
        // notes: http://whatismyipaddress.com/private-ip

        var internalIpRanges = Enumerable
            .Range(16, 31)
            .Select(i => "172.{0}.".FormatWith(i))
            .Concat(new[] {"192.168.", "10.", "127."})
            .ToArray();

        return ipAddress.StartsWith(internalIpRanges);
    }