Email Validation Function

Email Validation Function:
CREATE FUNCTION dbo.IsEmailValid (@Email varchar (100))
RETURNS BIT
AS
BEGIN
/*
One instance of @, multiple dots, atleast one after @
no space
after the last dot minimum 2 chars, max 3 chars
some chars between @ and .
No Special Chars
*/
DECLARE @atpos int, @dotpos int
SET @Email = LTRIM(RTRIM(@Email)) -- remove leading and trailing blanks
IF LEN(@Email) = 0 RETURN(0) -- nothing to validate
SET @atpos = charindex('@',@Email) -- position of first (hopefully only) @
IF @atpos <= 1 OR @atpos = LEN(@Email) RETURN(0) -- @ is neither 1st or last or missing
IF CHARINDEX('@', @email, @atpos+1) > 0 RETURN(0) -- Two @s are illegal
IF CHARINDEX(' ',@Email) > 0 RETURN(0) -- Embedded blanks are illegal
SET @dotpos = CHARINDEX('.',Reverse(@Email)) -- location (from rear) of last dot
IF (@dotpos <> 4) or (LEN(@Email) - @dotpos) < @atpos RETURN (0) -- dot / 2 or 3 char, after @
if (@atpos + @dotpos = len(@email)) Return (0) -- Nothing between @ and .
-- Special Characters Scan
Declare @emaillen int, @currpos int, @currascii int
SET @emaillen = LEN(@email)
SET @currpos = 0
WHILE @emaillen != @currpos
BEGIN
SET @currpos = @currpos + 1
SET @currascii = ASCII(substring(@email, @currpos, 1))
if @currascii <= 44 Return (0)
if @currascii = 47 Return (0)
if @currascii >= 58 and @currascii <= 63 Return (0)
if @currascii >= 91 and @currascii <= 94 Return (0)
if @currascii = 96 Return (0)
if @currascii >= 123 Return (0)
END
RETURN(1) -- Hope this is a valid email
END