[plug] VPNs

[Rob Hall]

Got a question for the routing Gurus out there.

An associate (of whom I mentioned in a mail yesterday - yes he is _very_
dangerous when left alone on a Linux box) has a client that is running a VPN
(Virtual Private Network) with Telstra.  What it constist of is:

SITE A
6 PC's connected to a router (Not sure what the address is)
They have IP addresses in the range of 10.3.26.? (I think)

SITE B
12 pcs connected to a router (Telstra set it up as 10.3.26.1)
IP addresses are 10.3.26.? (I am sure about this one)

Both sites are connected by ISDN over the internet.  They broadcast over a
registered internet IP address.

Now SITE A has a Windoze based accounting system served from a Linux box
that they want access from SITE B.

Now my understanding of IP networking is that it is impossible for one of
these networks to have direct access to the other as long as they are
separated by the internet IP address.  I thought that at least all servers
and routers would need Class C addresses.

Could it be that the routers actually have a Class C address and that they
do some sort of IPchains (or ipfwadm) equivalent thing and just forward the
requests on to the local server?  In that case, to map the drives (in
Windows) on the server at SITE B from SITE A would require you to use the
Class C address.  Is this correct?

Sorry about the vagueness of detail.  My associate is a bit vague on giving
them to me.

This is my understanding of how a VPN works anyway.

Any enlightenment on the topic would be appreciated.


Regards,


Rob Hall


~~~~~~~~~~~~~~~~~~~~~
Heights Computer Management
"Making computers work for you."

rhall at student.ecu.edu.au
www.hcm.iinet.net.au

08 9342 2664
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