/// <summary>
/// Determines whether an address is in a subnet specified by an <see cref="IPAddress" /> and subnet mask.
/// </summary>
/// <param name="address">The <see cref="IPAddress" /> to test.</param>
/// <param name="subnetAddress">An <see cref="IPAddress" /> that is in the desired subnet.</param>
/// <param name="subnetMask">The subnet mask.</param>
/// <returns><c>true</c> if the address is in the subnet indicated by the specified address and mask; otherwise, <c>false</c>.</returns>
/// <exception cref="ArgumentNullException">
/// <paramref name="address" /> is null.
/// <para>or</para>
/// <paramref name="subnetAddress" /> is null.
/// <para>or</para>
/// <paramref name="subnetMask" /> is null.
/// </exception>
public static bool IsInSubnet(this IPAddress address, IPAddress subnetAddress, IPAddress subnetMask)
{
if (address == null)
{
throw new ArgumentNullException(nameof(address));
}
if (subnetAddress == null)
{
throw new ArgumentNullException(nameof(subnetAddress));
}
if (subnetMask == null)
{
throw new ArgumentNullException(nameof(subnetMask));
}
IPAddress network1 = subnetAddress.ApplySubnetMask(subnetMask);
IPAddress network2 = address.ApplySubnetMask(subnetMask);
return(network1.Equals(network2));
}