# PHP - POST string containing \>\< causes error

**URL:** <https://forum.kirupa.com/t/php-post-string-containing-causes-error/323996>\
**Category:** programming\
**Created:** [July 27, 2011, 2:30pm UTC](https://forum.kirupa.com/t/php-post-string-containing-causes-error/323996 "2011-07-27T14:30:49Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![kill\_robot\_kill](https://yyz1.discourse-cdn.com/flex011/user_avatar/forum.kirupa.com/kill_robot_kill/32/359_2.png) [@kill\_robot\_kill](https://forum.kirupa.com/u/kill_robot_kill)\
**Post date:** [July 27, 2011, 2:30pm UTC](https://forum.kirupa.com/t/php-post-string-containing-causes-error/323996/1 "2011-07-27T14:30:49Z")

</div>

PHP POST String containing \>\< causes 500 Internal Server Error

I am trying to figure out why on one of my servers (Linux - php 5.3.6) I am getting an error when I try to POST a string containing “\>\<” but on another server (Linux - php 5.2.17) I am not getting an error.

I’ve tried these functions to sorta sanitize the data

addslashes()  
htmlentities()  
htmlspecialchars()  
mysql\_real\_escape\_string()  
strip\_tags()

All of them fail on the 5.3.6 server when the posted string contains “\>\<”. Is there a function/setting I’m missing. This has throughly confused me.

This is the error I’m getting:  
Forbidden  
You don’t have permission to access post.php on this server.  
Additionally, a 500 Internal Server Error error was encountered while trying to use an ErrorDocument to handle the request