All network traffic causes memory leak
 

On our newly setup Debian Etch server, it seems any network traffic including ftp and http consumes an almost equal amount of memory. It's so extreme that, upon booting up with Apache auto started, you can watch the used ram keep rising hundreds of MB. The machine has 2GB of ram, but within hours, it's all in use. If you check "top" for any process actually responsible for it all, you won't find anything - it's all in check.

I've tried reinstalling the entire OS, but nothing.

If your swap partition/files isn't also filling up, then that's normal behaviour, not a leak. Linux will take all of the memory it can get but that doesn't mean it's used/leaking. Have a look at the article at http://gentoo-wiki.com/FAQ_Linux_Memory_Management for a good explanation of this.

I am a fool..

Thanks!

Not at all - it's not obvious unless you already know about it...