Help with email validation code

[leafgreen]

What's the purpose of the part with "example.com"? Is it to make an exception for email addresses ending with example.com? If so, how can I excise this part only, keeping the rest of the script functional?
TIA!

[fixed]
function ValidateMail($Email)
{
global $HTTP_HOST;
$result = array();
if (!eregi("^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,3})$", $Email))
{
 $result[0]=false;
 $result[1]="$Email is not properly formatted";
 return $result;
}
list ( $Username, $Domain ) = split ("@",$Email);
if($Email!="[b]example.com[/b]")
{
 $result[0]=true;
 $result[1]="$Email appears to be valid.";
 return $result;
}
else
{
if (getmxrr($Domain, $MXHost))
{
$ConnectAddress = $MXHost[0];
}
else
{
$ConnectAddress = $Domain;
}
$Connect = fsockopen ( $ConnectAddress, 25 );
if ($Connect)
{
if (ereg("^220", $Out = fgets($Connect, 1024)))
{
fputs ($Connect, "HELO $HTTP_HOST\r\n");
$Out = fgets ( $Connect, 1024 );
fputs ($Connect, "MAIL FROM: <{$Email}>\r\n");
$From = fgets ( $Connect, 1024 );
fputs ($Connect, "RCPT TO: <{$Email}>\r\n");
$To = fgets ($Connect, 1024);
fputs ($Connect, "QUIT\r\n");
fclose($Connect);
if (!ereg ("^250", $From) ¦¦
!ereg ( "^250", $To ))
{
$result[0]=false;
$result[1]="Server rejected address.";
return $result;
}
}
else
{
$result[0] = false;
$result[1] = "No response from server.";
return $result;
}
}
else
{
$result[0]=false;
$result[1]="Sorry, but for some reason we cannot connect to your email server.";
return $result;
}
$result[0]=true;
$result[1]="$Email appears to be valid.";
return $result;
}
} 
?>
[/fixed]

[edited by: coopster at 12:54 am (utc) on Jan. 16, 2008]

[edited by: eelixduppy at 1:41 pm (utc) on Jan. 17, 2008]
[edit reason] generalized domain [/edit]

[eelixduppy]

The script checks to make sure that the email string (the entire thing) isn't example.com. So [e-mail] is still valid according to this script.

[PHP_Chimp]

You may want to think about your email validation routine a little, as there are plenty of valid characters that you are not allowing. While most people emails only have [a-z0-9_-] in them that is not the only characters allowed. So if you are going to tell people

$result="$Email is not properly formatted";

when there email is perfectly well formatted you are going to annoy people.
Seeing as you are actually doing a lookup on the address that people specify why dont you do the lookup first then tel them there email address doesnt work. Or if you dont want to do that then instead of kicking them out give a "Are you really sure this email address is correct" message, then if they say yes do your lookup.

[eelixduppy]

Just a note. The following link is a very good resource for email validation regex: [regular-expressions.info...]

There are some interesting points brought up, too.

[mjwalshe]

id use a regex to do this theres a good if EXTREAMLY SCARRY! one in the small owls book - which has an entire chaper on email validation.

[oreilly.com...]

[jatar_k]

there is also this thread from our Library
[webmasterworld.com...]

it has links to a couple other great threads