WCF Service Behavior Example: IPFilter - Allow/Deny Access by IP Address

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Security.Cryptography;

namespace IPFilterTests
{


    public static class RandomUtil
    {
        private static readonly char[] _randomStringValues = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789".ToCharArray();

        public static string CreateRandomString(int length)
        {
            return CreateRandomString(length, _randomStringValues);
        }
        public static string CreateRandomString(int length, char[] values)
        {
            // Get the seed.
            int seed = GetSeed();
            // Create the random class
            Random rnd = new Random(seed);
            // Create array for password.
            char[] str = new char[length];
            int valueLen = values.Length;


            for (int i = 0; i < str.Length; i++)
            {
                str[i] = values[rnd.Next(0, valueLen - 1)];
            }
            return new string(str);
        }

        private static int GetSeed()
        {
            byte[] bytes = new byte[4];
            RandomNumberGenerator rng = RandomNumberGenerator.Create();
            rng.GetBytes(bytes);

            return
                bytes[0] |
                bytes[1] << 8 |
                bytes[2] << 16 |
                bytes[3] << 24;
        }
    }
}