Datatype for storing ip address in SQL Server

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What datatype should I choose for storing an IP Address in a SQL Server?

By selecting the right datatype would it be easy enough to filter by IP address then?

12 Answers

The following answer is based on answers by M. Turnhout and Jerry Birchler to this question but with the following improvements:

  • Replaced the use of undocumented functions (sys.fn_varbintohexsubstring, fn_varbintohexstr) with CONVERT() for binary styles
  • Replaced XML "hacks" ( CAST('' as xml).value('xs:hexBinary()) ) with CONVERT() for binary styles
  • Fixed bug in Jerry Birchler's implementation of fn_ConvertIpAddressToBinary (as pointed out by C.Plock)
  • Add minor syntax sugar

The code has been tested in SQL Server 2014 and SQL Server 2016 (see test cases at the end)

IPAddressVarbinaryToString

Converts 4 bytes values to IPV4 and 16 byte values to IPV6 string representations. Note that this function does not shorten addresses.

ALTER FUNCTION dbo.IPAddressVarbinaryToString
(
    @varbinaryValue VARBINARY( 16 )
)
RETURNS VARCHAR(39)
AS
BEGIN
    IF @varbinaryValue IS NULL
        RETURN NULL;
    ELSE IF DATALENGTH( @varbinaryValue ) = 4
        RETURN 
            CONVERT( VARCHAR(3), CONVERT(TINYINT, SUBSTRING( @varbinaryValue, 1, 1 ))) + '.' +
            CONVERT( VARCHAR(3), CONVERT(TINYINT, SUBSTRING( @varbinaryValue, 2, 1 ))) + '.' +
            CONVERT( VARCHAR(3), CONVERT(TINYINT, SUBSTRING( @varbinaryValue, 3, 1 ))) + '.' +
            CONVERT( VARCHAR(3), CONVERT(TINYINT, SUBSTRING( @varbinaryValue, 4, 1 )));
    ELSE IF DATALENGTH( @varbinaryValue ) = 16
        RETURN 
            CONVERT( VARCHAR(4), SUBSTRING( @varbinaryValue,  1, 2 ), 2 ) + ':' +
            CONVERT( VARCHAR(4), SUBSTRING( @varbinaryValue,  3, 2 ), 2 ) + ':' +
            CONVERT( VARCHAR(4), SUBSTRING( @varbinaryValue,  5, 2 ), 2 ) + ':' +
            CONVERT( VARCHAR(4), SUBSTRING( @varbinaryValue,  7, 2 ), 2 ) + ':' +
            CONVERT( VARCHAR(4), SUBSTRING( @varbinaryValue,  9, 2 ), 2 ) + ':' +
            CONVERT( VARCHAR(4), SUBSTRING( @varbinaryValue, 11, 2 ), 2 ) + ':' +
            CONVERT( VARCHAR(4), SUBSTRING( @varbinaryValue, 13, 2 ), 2 ) + ':' +
            CONVERT( VARCHAR(4), SUBSTRING( @varbinaryValue, 15, 2 ), 2 );

    RETURN 'Invalid';
END

Test Cases:

SELECT dbo.IPAddressVarbinaryToString(0x00000000000000000000000000000000) -- 0000:0000:0000:0000:0000:0000:0000:0000 (no address shortening)
SELECT dbo.IPAddressVarbinaryToString(0x00010002000300400500060070000089) -- 0001:0002:0003:0040:0500:0600:7000:0089
SELECT dbo.IPAddressVarbinaryToString(0xC0A80148) -- 255.168.1.72
SELECT dbo.IPAddressVarbinaryToString(0x7F000001) -- 127.0.0.1 (no address shortening)
SELECT dbo.IPAddressVarbinaryToString(NULL) -- NULL

IPAddressStringToVarbinary

Converts IPV4 and IPV6 string representations to 4 byte and 16 bytes binary values respectively. Note that this function is able to parse most (all of the commonly used) of shorthand address representations (e.g. 127...1 and 2001:db8::1319:370:7348). To force this function to always return 16 byte binary values uncomment leading 0s concatenation at the end of the function.

ALTER FUNCTION [dbo].[IPAddressStringToVarbinary]
(
    @IPAddress VARCHAR( 39 )
)
RETURNS VARBINARY(16) AS
BEGIN

IF @ipAddress IS NULL
    RETURN NULL;

DECLARE @bytes VARBINARY(16), @token VARCHAR(4),
    @vbytes VARBINARY(16) = 0x, @vbzone VARBINARY(2),
    @tIPAddress VARCHAR( 40 ),
    @colIndex TINYINT,
    @delim CHAR(1) = '.',
    @prevColIndex TINYINT = 0,
    @parts TINYINT = 0, @limit TINYINT = 4;

-- Get position if IPV4 delimiter
SET @colIndex = CHARINDEX( @delim, @ipAddress );

-- If not IPV4, then assume IPV6
IF @colIndex = 0
BEGIN
    SELECT @delim = ':', @limit = 8, @colIndex = CHARINDEX( @delim, @ipAddress );

    -- Get number of parts (delimiters)
    WHILE @colIndex > 0
        SELECT @parts += 1, @colIndex = CHARINDEX( @delim, @ipAddress, @colIndex + 1 );

    SET @colIndex = CHARINDEX( @delim, @ipAddress );

    IF @colIndex = 0
        RETURN NULL;
END

-- Add trailing delimiter (need new variable of larger size)
SET @tIPAddress = @IPAddress + @delim;

WHILE @colIndex > 0
BEGIN
    SET @token = SUBSTRING( @tIPAddress, @prevColIndex + 1, @Colindex - @prevColIndex - 1 );

    IF @delim = ':'
    BEGIN
        SELECT @vbzone = CONVERT( VARBINARY(2), RIGHT( '0000' + @token, 4 ), 2 ), @vbytes += @vbzone;

        -- Handles consecutive sections of zeros representation rule (i.e. ::)(https://en.wikipedia.org/wiki/IPv6#Address_representation)
        IF @token = ''
            WHILE @parts + 1 < @limit
                SELECT @vbytes += @vbzone, @parts += 1;
    END
    ELSE
    BEGIN
        SELECT @vbzone = CONVERT( VARBINARY(1), CONVERT( TINYINT, @token )), @vbytes += @vbzone
    END

    SELECT @prevColIndex = @colIndex, @colIndex = CHARINDEX( @delim, @tIPAddress, @colIndex + 1 ) 
END

SET @bytes =
    CASE @delim
        WHEN ':' THEN @vbytes
        ELSE /*0x000000000000000000000000 +*/ @vbytes -- Return IPV4 addresses as 4 byte binary (uncomment leading 0s section to force 16 byte binary)
    END 

RETURN @bytes

END

Test Cases

Valid cases

SELECT dbo.IPAddressStringToVarbinary( '0000:0000:0000:0000:0000:0000:0000:0001' ) -- 0x0000000000000000000000000001 (check bug fix)
SELECT dbo.IPAddressStringToVarbinary( '0001:0002:0003:0040:0500:0600:7000:0089' ) -- 0x00010002000300400500060070000089
SELECT dbo.IPAddressStringToVarbinary( '2001:db8:85a3:8d3:1319::370:7348' )     -- 0x20010DB885A308D31319000003707348 (check short hand)
SELECT dbo.IPAddressStringToVarbinary( '2001:db8:85a3:8d3:1319:0000:370:7348' ) -- 0x20010DB885A308D31319000003707348
SELECT dbo.IPAddressStringToVarbinary( '192.168.1.72' ) -- 0xC0A80148
SELECT dbo.IPAddressStringToVarbinary( '127...1' ) -- 0x7F000001 (check short hand)
SELECT dbo.IPAddressStringToVarbinary( NULL ) -- NULL
SELECT dbo.IPAddressStringToVarbinary( '' ) -- NULL
-- Check that conversions return original address
SELECT dbo.IPAddressVarbinaryToString( dbo.IPAddressStringToVarbinary( '0001:0002:0003:0040:0500:0600:7000:0089' )) -- '0001:0002:0003:0040:0500:0600:7000:0089' 
SELECT dbo.IPAddressVarbinaryToString( dbo.IPAddressStringToVarbinary( '127...1' )) -- 127.0.0.1
SELECT dbo.IPAddressVarbinaryToString( dbo.IPAddressStringToVarbinary( '192.168.1.72' )) -- 192.168.1.72
SELECT dbo.IPAddressVarbinaryToString( dbo.IPAddressStringToVarbinary( '2001:db8:85a3:8d3:1319::370:7348' ))     -- 2001:0db8:85a3:08d3:1319:0000:0370:7348
SELECT dbo.IPAddressVarbinaryToString( dbo.IPAddressStringToVarbinary( '2001:db8:85a3:8d3:1314:0000:370:7348' )) -- 2001:0db8:85a3:08d3:1319:0000:0370:7348
SELECT dbo.IPAddressVarbinaryToString( dbo.IPAddressStringToVarbinary( '2001:db8:85a3:8d3::370:7348' )) -- 2001:0DB8:85A3:08D3:0000:0000:0370:7348
-- This is technically an invalid IPV6 (according to Wikipedia) but it parses correctly
SELECT dbo.IPAddressVarbinaryToString( dbo.IPAddressStringToVarbinary( '2001:db8::1319::370:7348' )) -- 2001:0DB8:0000:0000:1319:0000:0370:7348

Invalid cases

SELECT dbo.IPAddressVarbinaryToString( dbo.IPAddressStringToVarbinary( '2001:db8::1319::7348' )) -- 2001:0DB8:0000:0000:0000:1319:0000:7348 (ambiguous address)
SELECT dbo.IPAddressStringToVarbinary( '127.1' ) -- 127.0.0.1 (not supported short-hand)
SELECT dbo.IPAddressVarbinaryToString( dbo.IPAddressStringToVarbinary( '127.1' )) -- 127.0.0.1 (not supported short-hand)
SELECT dbo.IPAddressStringToVarbinary( '0300.0000.0002.0353' ) -- octal byte values
SELECT dbo.IPAddressStringToVarbinary( '0xC0.0x00.0x02.0xEB' ) -- hex values
SELECT dbo.IPAddressStringToVarbinary( 'C0.00.02.EB' ) -- hex values

We do a lot of work where we need to figure out which IP's are within certain subnets. I've found that the simplest and most reliable way to do this is:

  1. Add a field to each table called IPInteger (bigint) (when invalid, set IP= '0.0.0.0')
  2. For smaller tables, I use a trigger that updates IPInteger on change
  3. For larger tables, I use a SPROC to refresh the IPIntegers
    ALTER FUNCTION [dbo].[IP_To_INT ]
    ( 
        @IP CHAR(15) 
    ) 
    RETURNS BIGINT 
    AS 
    BEGIN 
        DECLARE @IntAns BIGINT, 
            @block1 BIGINT, 
            @block2 BIGINT, 
            @block3 BIGINT, 
            @block4 BIGINT, 
            @base BIGINT 
     
        SELECT 
            @block1 = CONVERT(BIGINT, PARSENAME(@IP, 4)), 
            @block2 = CONVERT(BIGINT, PARSENAME(@IP, 3)), 
            @block3 = CONVERT(BIGINT, PARSENAME(@IP, 2)), 
            @block4 = CONVERT(BIGINT, PARSENAME(@IP, 1)) 
     
        IF (@block1 BETWEEN 0 AND 255) 
            AND (@block2 BETWEEN 0 AND 255) 
            AND (@block3 BETWEEN 0 AND 255) 
            AND (@block4 BETWEEN 0 AND 255) 
        BEGIN      
            SET @base = CONVERT(BIGINT, @block1 * 16777216)
            SET @IntAns = @base +  
                (@block2 * 65536) +  
                (@block3 * 256) + 
                (@block4) 
        END 
        ELSE 
            SET @IntAns = -1 
        RETURN @IntAns 
    END
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