acess my external ip from insternal lan

I have an DSL Modem and Router. The router obtains a public IP from my ISP.
The router also acts as a dhcp server and hands out 192.168.0.X numbers. I
have port fowarding setup to foward port calls to my computer acting as a
webserver. It is a win XP pro machine running IIS. I can access the
webserver from any internal PC using the internal IP of the webserver but not
the external IP. I can also access the webserver from any external PC by
using the public IP. My problem is that i can not access my webserver
internally by using the public IP. I want to eventually register a domain
name and use a dynamic IP updater, but i want to fix this problem first. I
hope someone can help me. This is pretty frustrating.

That's the way it works. If you are inside a router, you need to use the
LAN IP address. You can't get to the "outside" of the router to use port
forwarding from inside.

"Tom" <(E-Mail Removed)> wrote in message
news:65627900-B49D-4ED6-9B86-(E-Mail Removed)...
>I have an DSL Modem and Router. The router obtains a public IP from my
>ISP.
> The router also acts as a dhcp server and hands out 192.168.0.X numbers.
> I
> have port fowarding setup to foward port calls to my computer acting as a
> webserver. It is a win XP pro machine running IIS. I can access the
> webserver from any internal PC using the internal IP of the webserver but
> not
> the external IP. I can also access the webserver from any external PC by
> using the public IP. My problem is that i can not access my webserver
> internally by using the public IP. I want to eventually register a domain
> name and use a dynamic IP updater, but i want to fix this problem first.
> I
> hope someone can help me. This is pretty frustrating.

NAT won't make "U-Turns" like that. It creates a situation where both the
source and destination MAC address in the packet are identical (the external
nic mac). It can't understand what to do with sending from itself to itself
and sort of shoots itself in the head.

If you were "publishing" the internal webserver to the outside with a proxy
(like ISA Server's Web Publishing feature) you could get by with it because
it is a different technology and works different than a "NAT box".

--

Phillip Windell [MCP, MVP, CCNA]
www.wandtv.com


"Tom" <(E-Mail Removed)> wrote in message
news:65627900-B49D-4ED6-9B86-(E-Mail Removed)...
> I have an DSL Modem and Router. The router obtains a public IP from my
ISP.
> The router also acts as a dhcp server and hands out 192.168.0.X numbers.
I
> have port fowarding setup to foward port calls to my computer acting as a
> webserver. It is a win XP pro machine running IIS. I can access the
> webserver from any internal PC using the internal IP of the webserver but
not
> the external IP. I can also access the webserver from any external PC by
> using the public IP. My problem is that i can not access my webserver
> internally by using the public IP. I want to eventually register a domain
> name and use a dynamic IP updater, but i want to fix this problem first.
I
> hope someone can help me. This is pretty frustrating.