Converting a string IP to an int and back

I often need to convert a string IP to an Int32 and then back again. To facilitate converting an Int32 to its string representation I have added this extension method to my IntExtensions class in C#:

public static class IntExtensions
{
    /// <summary>
    /// Converts an integer that represents an IPv4 to the string equivalent
    /// Source: http://guyellisrocks.com/coding/converting-a-string-ip-to-an-int-and-back/
    /// </summary>
    /// <param name="solidIP">The integer representation of an IPv4</param>
    /// <returns>A string of the format x.x.x.x representing an IPv4</returns>
    public static string ToIPv4(this int solidIP)
    {
        byte ip1 = (byte)(solidIP >> 24);
        byte ip2 = (byte)(solidIP >> 16);
        byte ip3 = (byte)(solidIP >> 8);
        byte ip4 = (byte)(solidIP);
        return ip1 + "." + ip2 + "." + ip3 + "." + ip4;
    }
}

And to convert the string representation of an IP to an Int32 I have added this extension method to my StringExtensions class:

public static class StringExtensions
{
    /// <summary>
    /// Converts a string that holds an IPv4 address with the pattern x.x.x.x
    /// to the integer equivalent. If the string cannot be split into 4 parts
    /// using a . or if the 4 parts cannot by parsed
    /// into bytes then 0 will be returned.
    /// Source: http://guyellisrocks.com/coding/converting-a-string-ip-to-an-int-and-back/
    /// </summary>
    /// <param name="IP">A string representing an IPv4 address</param>
    /// <returns>An integer representing an IPv4 address or zero if failure</returns>
    public static int ToIPv4(this string IP)
    {
        try
        {
            string[] fourIP = IP.Split('.');

            Int32 ip =
                (Byte.Parse(fourIP[0]) << 24) +
                (Byte.Parse(fourIP[1]) << 16) +
                (Byte.Parse(fourIP[2]) << 8) +
                Byte.Parse(fourIP[3]);

            return ip;
        }
        catch
        {
            return 0;
        }
    }
}