PHP FILTER VALIDATE EMAIL does not work correctly

Question

I employ PHP 5.3.10. Here is the code:

<?php
$email = "test@example.c";
if (filter_var($email, FILTER_VALIDATE_EMAIL))
        echo "Email: ".$email." correct";
else
        echo "email not correct";
?>

"Email: test@example.c correct," it responds.

According to this list: https://data.iana.org/TLD/tlds-alpha-by-domain.txt , I'm not aware of any top level domains (TLDs) that are only one character in length.

Therefore, is the FILTER VALIDATE EMAIL filter functioning properly or not?

Answer 1

It can be difficult to verify email addresses. Look at the following list:

Valid email addresses

1. niceandsimple@example.com
2. very.common@example.com
3. a.little.lengthy.but.fine@dept.example.com
4. disposable.style.email.with+symbol@example.com
5. user@[IPv6:2001:db8:1ff::a0b:dbd0]
6. "much.more unusual"@example.com
7. "very.unusual.@.unusual.com"@example.com
8. "very.(),:;<>[]".VERY."very@\ "very".unusual"@strange.example.com
9. postbox@com (top-level domains are valid hostnames)
10. admin@mailserver1 (local domain name with no TLD)
11. !#$%&'*+-/=?^_`{}|~@example.org
12. "()<>[]:,;@\"!#$%&'*+-/=?^_`{}| ~.a"@example.org
13. " "@example.org (space between the quotes)
14. üñîçøðé@example.com (Unicode characters in local part)

Invalid email addresses

1. Abc.example.com (an @ character must separate the local and domain parts)
2. A@b@c@example.com (only one @ is allowed outside quotation marks)
3. a"b(c)d,e:f;gi[j\k]l@example.com (none of the special characters in this local part are allowed outside quotation marks)
4. just"not"right@example.com (quoted strings must be dot separated, or the only element making up the local-part)
5. this is"not\allowed@example.com (spaces, quotes, and backslashes may only exist when within quoted strings and preceded by a backslash)
6. this\ still"not\allowed@example.com (even if escaped (preceded by a backslash), spaces, quotes, and backslashes must still be contained by quotes)

Nearly every email validation implementation is "bugged," however the php implementation is fine to use because it accepts all widely used email addresses.