I have index.php with only one line in it
<?php echo $_GET['a']; ?>
And also I have a .htaccess with only two lines in it
RewriteEngine on
RewriteRule ^([a-z]+)$ ?a=$1
Why when I enter /ab.cd I get a 404 error, but if I entering /abcd. it doesn't give me a 404 error and PHP echos abcd (without the dot on the end of the url).
Can anybody tell me why my rewrite rule allows abcd. through instead of giving me a 404 error?
EDIT:
I've just tested your Rewriterule (standalone) in my dev environment and it works. It doesn't allow /abcd. through on mine - It gives me a 404 error, so there must be something somewhere in your environment that's affecting your rules.
-initial post-
Looks like the period(.) in your /ab.cd isn't defined in the Rewriterule - just lowercase a-z chars.
Use:
RewriteEngine on
RewriteRule ^([a-z.]+)$ ?a=$1
^
The regular expression you've used, ([a-z]+), matches only the lowercase letters "a" through "z". It will never match a series of letters followed by a period followed by a series of letters, like your attempt with ab.cd.
If you want to match periods as well, you need ([a-z.]+).
I just rebuilt the situation on my server and I'm getting the desired 404 error. I only added the [L] flag to the RewriteRule.
.htaccess
RewriteEngine on
RewriteRule ^([a-z]+)$ test.php?a=$1 [L]
test.php
<?php echo $_GET['a']; ?>
Are there maybe any other rewrite rules following that might interfere with your request? Even in other files that get included? In that case, the L flag might help you.