[CentOS] Centos 6 - Networking: Some Queries -- GURUS HELP PL

Wed Jun 13 15:42:22 UTC 2012
Les Mikesell <lesmikesell at gmail.com>

On Wed, Jun 13, 2012 at 1:52 AM, Sanjay Arora <sanjay.k.arora at gmail.com> wrote:
>> It might be easier to suggest an approach if you describe what you
>> need to do.  You can't magically make new public addresses that aren't
>> available appear on an existing network, whether it is on real or
>> virtual NICs.     But there are ways to tunnel access to different
>> private networks to each other or to reverse-proxy connections to a
>> public address to a server on a private address.
> My machine is on LAN, has an IP of This
> Network has GW which is an adsl router in the office. No
> firewall on the router. Other LAN machines have IPs in the
> network & I'm not allowed to use those IPs. They are
> reserved for LAN use.

OK, I don't quite understand what 'reserved for LAN' use means.   I'll
assume it means someone else controls it and they won't cooperate if
you bridge you VM's to the LAN.   In most scenarios, the adsl router
would give out DHCP addresses and unless you run out, bridged machines
would just grab their own address and work just like a new physical

> Now My machine has a second card for LTSP Network (it is a LTSP
> Server) with IP
> I want Virtual hosts on my machine so I have to have a different IP
> range....say
> And I want routing among three as well as Internet access through the
> NATTED adsl router which has a dynamic IP.
> This is my problem.

You still don't say what kind of access you need - or why you can't
bridge on the side which eliminates half of the problem.
Outbound connections are easy - your LTSP clients probably already
have that via NAT on the server, and they also should be using the
server as their default gateway.   If you don't want the VM guests on
the same subnet, you can create a new guest-only subnet with the same
setup as the LTSP side (server is default gateway and can route among
all networks).     So you only have a problem if you need to accept
inbound connections from the LAN or internet.  You probably don't have
that now for the LTSP subnet.  Do you need it for the VMs?

   Les Mikesell
     lesmikesell at gmail.com