Accessing internal network resource using external IP address

Question

How is it possible to access an internal resource (email server / FTP server) using its external IP address but from within the network ?

The situation is that a number of users have laptops and work out of the office several days per week. I don't want them to have to change the connection details from 217.x.x.x to 10.0.0.x every time they come into the office, then back again when they leave.

I have external access working, so they can connect using the 217.x.x.x IP when on the road, but it doesn't work when they are in the office.

We have a router providing NAT access to the net and different servers for FTP, email etc.

Answer 1

Unless you have filters forbidding access to the external NAT'ed address from internal clients, I do not see why it should not work.

Answer 2

This is what DNS is for - your external DNS provides the 217.x.x.x address for the names, while your internal DNS returns the 10.0.0.x IP address. Clients access resources by hostname, not IP address, and it's done.

Answer 3

Dear sir, i have netgear router model wgr614v7 and i want access my ip camera which is connected to router internal network so please tell me how access my camera from internet using external ip and what will the port no.

Answer 4

I have a similar issue I would like to ftp (put) to a pc knowing the external ip and using the hostname or internal ip address, can someone tell me how (set up router, etc.). Thanks