Re: access to IP address for a machine on inet behind a firewall?
On Sun, 24 Feb 2002 13:33:40 +1000 Alan E. Davis <adavis@saipan.com>
wrote:
> 4 machines in my classroom are attached to a private IP LAN, which is
> attached through a gateway to the Inet. I can FTP and so forth from
> these machines, but I cannot access them directly through the IP
> addresses I have been assigned. I want to set up a web server and
> also to have access to these machines from home.
Because your "interior" LAN boxen have private addresses, you can
not directly address them from the outside. That's why they have
private, or non-routable addresses. Otherwise, if you could access
them, then there's a route, so they'd need public, routable addresses!
Get it? Or am I rambling incoherently?
Along comes port-forwarding. Configure it on the firewall and it
allows you to, well, forward all the incoming packets directed at
port X on the firewall to port Y (which may equal X) on an interal
machine.
So, If the firewall has IPs 12.34.56.78 and 192.168.1.1, and 3
internal machines 192.168.1.2, 192.168.1.3 and 192.168.1.4, then
I could put an externally accessably http daemon on 192.168.1.3
and ftp daemon on 192.168.1.4.
The ftp and http could both be on 192.168.1.2, but can not have
http daemons on 192.168.1.2 & 192.168.1.3.
Note!! ftp is almost as evil as telnet, since it is just as insecure.
> Is it possible to discover what INET IP addresses are assigned to
> these machines (if any)? How can I learn what IP address a machine
> outside the LAN associates with my machine?
No, but ssh is your friend! ssh to the firewall, then from there,
ssh to any other internal
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