This same problem happened a couple of years ago on the DNS-321:
http://forums.dlink.com/index.php?topic=2880
Here's the problem: (from that thread)
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Here's what I see in the source JavaScript, the part that hides the "all" box:
function ChkSecurity()
{
//to show All accounts or not
var security='USER';
if(security=="USER")
document.getElementById("all_account").style.display = "none";
else
document.getElementById("all_account").style.display = "";
}
No wonder it hides it....
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What you have to do is:
-Disable javascript in Firefox
-Reload the page
-Now the checkbox will be there, check it
-Re enable javascript
-reload the page and save.