Can not use our external IP from LAN. Work fine from WAN
Posted on 2010-01-04
I have an odd problem that I can not resolve.
For the sake of demonstration I use example IP addresses (not the real ones)
We have 2 terminal Servers behind a router and proxy server.
Terminal Server 1 has the proxy software program installed. It has 2 netcard. one to the router and one to Lan. The proxy program is setup with port forwarding and filtering for the students internet.
Terminal Server 2 is totally behind the Proxy with 1 netcard. All comunication goes through Terminal Server 1's proxy.
On Lan everyone can access Terminal Server 1 and 2 using IP or Domain Name. This is working as it should.
For all the teachers, I have given our External IP so they can access the Terminal Servers from home. This is also working fine. Router has been setup to forward port coms for the 2 servers to our Proxy Server. Proxy server then forward one port to itself and one to terminal server2.
All happy, all working
Here is the problem.
When the teachers come to school, they sit on LAN and try to connect using External IP. Now it does not work. I am working with several schools and no problems else where.
We want to get this to work so the teachers do not have to change their settings based on if at home or on schools LAN.
Does anyone have an idea why I can not sit on Lan using my WAN ip to connect via RDP?
I was thinking if its possible for me to write something into local DNS Server (that all are using) so when writing WAN ip or domain name it can do the lookup on our own DNS and then connect straight away. Can this be done? If Yes can someone explain howto?
if not how to I go ahead trouble shooting this?