write to file security?

[newbe]

I need to write to a file so I set the security on a folder on my web server to allow read and write.

Isn't there some way someone could set up there own server and then link and write to my file? It there any way I can secure this? As I am writing an HTML for a table and then linking it to the pages.

thanks

[michael]

Deny access with .htaccess, and then include the file in PHP.
Never leave a PHP file open with write access for everybody.

[newbe]

i use IIS for windows 2000 server.
I don't think it has an .httaccs file. How do I inlclude it in PHP.

okay, so I set the file for only read only acces by everybody.
Now how does PHP access it?