CREATE FUNCTION [dbo].[ipTxtToBin] 
( 
    @ip varchar(15) 
) 
RETURNS binary(4)
AS 
BEGIN 
    DECLARE @o1 binary(1), @o2 binary(1), @o3 binary(1), @o4 binary(1) 
    SELECT 
        @o1 = CONVERT(binary(1),CONVERT(tinyint,PARSENAME(@ip,4))), 
        @o2 = CONVERT(binary(1),CONVERT(tinyint,PARSENAME(@ip,3))),  
        @o3 = CONVERT(binary(1),CONVERT(tinyint,PARSENAME(@ip,2))), 
        @o4 = CONVERT(binary(1),CONVERT(tinyint,PARSENAME(@ip,1)))  
    RETURN @o1+@o2+@o3+@o4
END

declare @ip VARCHAR(15) 
set @ip = '255.128.64.32'
declare @bin binary(4)
select @bin = [dbo].[ipTxtToBin] (@ip)
select	  @ip as ip
		, @bin as bin
		, convert(tinyint,substring(@bin,1,1)) as octet1
		, convert(tinyint,substring(@bin,2,1)) as octet2
		, convert(tinyint,substring(@bin,3,1)) as octet3
		, convert(tinyint,substring(@bin,4,1)) as octet4