Unable to open page from outside of LAN

I have Win2000 and installed IIS, and computer is connected to Internet
trough D-Link DI-604 router.

I can open web page (default.htm in wwwroot) from computers in LAN using IP
address of host computer, but I can't open this page using URL address of my
router (i.e. I can't open this page from some computer over Internet).

There are cases when I can open this page using URL of router, but just
immediately after I opened that page from some computer in LAN.

Do somebody know why this is happening and how to solve this?

"Egbert Nierop (MVP for IIS)" <egbert_nierop.RemoveThis@nospam.invalid> wrote in
message news:ONAZOl85FHA.3296@TK2MSFTNGP09.phx.gbl...
>
> "Ivan Hrsto" <gallinarius.RemoveThis@hotmail.com> wrote in message
> news:%23lTTfX35FHA.3296@TK2MSFTNGP09.phx.gbl...
> >I have Win2000 and installed IIS, and computer is connected to Internet
> > trough D-Link DI-604 router.
> >
> > I can open web page (default.htm in wwwroot) from computers in LAN using
> > IP
> > address of host computer, but I can't open this page using URL address
of
> > my
> > router (i.e. I can't open this page from some computer over Internet).
> >
> > There are cases when I can open this page using URL of router, but just
> > immediately after I opened that page from some computer in LAN.
> >
> > Do somebody know why this is happening and how to solve this?
>
> Your router normally hides an internal IP subnetmask, which is normally
not
> accessable from external sources.
> Your router, should be configured, to pass (forward) port 80 to your
> internal web server. This way, it should work.

Router is already configured to forward port 80. It must be something else.