Dear Flavio, Yes ! I think this is what I am expecting for. Seems I need to check out the VPN "howto" then. Thanks, Raymond. Flavio Arthur Leal Ferreira wrote:

What about this alternative:

you use freeswan to establish two VPN: when site1 connects to internet it establishes one VPN with site 3; when site2 connects to internet it establishes one VPN with site 3;

site 3 routes traffic to the internal network address (fixed) of site 1 and 2 via its corresponding logical VPN interfaces.

Site 1, when connected, has a route to site2's internal network address(fixed) through its logical VPN interface;

Site 2, when connected, has a route to site1's internal network address(fixed) through its logical VPN interface;

telnets, ..., are made using internal network addresses of the destination LAN.

...

Raymond Fung wrote: I have an interesting idea here, but don't know if it is feasible to implement nor what kind of tools are needed to implement so. The situation is as follow :

There are 3 physically disjointed sites, all are LAN of computers. Two of the sites (namely site 1 and site 2) connects to the Internet through some masquerading / NAT device using dial-up connections (thus using dynamic IP and private IPs), while the third site (site 3) has fixed IP address. Now, computers in site 1 wants to telnet into computers in site 2. As both sites doesn't have fixed IP, can I make use of site 3 such that some software is run on a host at site 3 waiting for connection from computers from site 1 and 2. After the two connection are made, something like a VPN can be established through this site 3 host to link site 1 and 2 together ? It would be great if I can do whatever service available (such as ftp, telnet etc.) between site 1 and site 2. This can be represented as the diagram below :