Generate a random mac address

Question

I am looking for a method in C# which generates a random MAC number. Google is pretty thin on that one.

Thx a lot

SOLUTION:

With the help of Yahia I was able to code the following solution. Thx again!

public static string GenerateMACAddress()
    {
        var sBuilder = new StringBuilder();
        var r = new Random();
        int number;
        byte b;
        for (int i = 0; i < 6; i++)
        {
            number = r.Next(0, 255);
            b = Convert.ToByte(number);
            if (i == 0)
            {
                b = setBit(b, 6); //--> set locally administered
                b = unsetBit(b, 7); // --> set unicast 
            }
            sBuilder.Append(number.ToString("X2"));
        }
        return sBuilder.ToString().ToUpper();
    }

    private static byte setBit(byte b, int BitNumber)
    {
        if (BitNumber < 8 && BitNumber > -1)
        {
            return (byte)(b | (byte)(0x01 << BitNumber));
        }
        else
        {
            throw new InvalidOperationException(
            "Der Wert für BitNumber " + BitNumber.ToString() + " war nicht im zulässigen Bereich! (BitNumber = (min)0 - (max)7)");
        }
    }

    private static byte unsetBit(byte b, int BitNumber)
    {
        if (BitNumber < 8 && BitNumber > -1)
        {
            return (byte)(b | (byte)(0x00 << BitNumber));
        }
        else
        {
            throw new InvalidOperationException(
            "Der Wert für BitNumber " + BitNumber.ToString() + " war nicht im zulässigen Bereich! (BitNumber = (min)0 - (max)7)");
        }
    }

Answer 1

A slightly less verbose solution (which I think still achieves the same outcome):

public static string GetRandomMacAddress()
{
    var random = new Random();
    var buffer = new byte[6];
    random.NextBytes(buffer);
    var result = String.Concat(buffer.Select(x => string.Format("{0}:", x.ToString("X2"))).ToArray());
    return result.TrimEnd(':');
}

This gives a formatted MAC, remove string.Format and Trim if unformatted is required

Answer 2

There is no such method in the .NET framework...

You will need to write one yourself - read the format description, use a random generator to get 6 random numbers between 0 and 255, setup the 2 relevant bits (for globally unique/locally administered) as need be and then transform the number to hex (i.e. X2, 2 digits per number, left padded with 0) and join these together with : as delimiter...