i just wondering about the network setup .  as i know , if the host act as a gate way it also should has an internal IP  so it can ping the umls .
if use a bridge ,  the bridge should be set of the external ip , and the umls will be setup the internal ip , and umls will use tapN,
but now in the host  if ping umls  obversily can't reach it (is that right just add a route to the host , umls can be reached ?
like that , tap0 address is,  uml1 address is , and in uml1 set network as  ip gateway is
and add route in host like that   addroute tap0 [this command maybe wrong , you just know the meaning]
is that right ?
).   i just don't understant  how tap works . so if you give me a practical setup ,will be very appreciated.
also "exec linux ubd0=... umid=mytest eth0=..." , if edit the .bash_profile like that ,  it means the user can't login the host  ? as he login the host ,will be redirect to uml ?  
my understood is that , if the user login just start a uml instance for him . but if the uml instance is already there , how should i do ?
thank you for your help . 

2006/6/19, Stefano Melchior <stefano.melchior@openlabs.it>:
On Sun, Jun 18, 2006 at 06:07:44PM +0800, paul john wrote:
Dear friend,
> as the subject,
>                       host has onely  one ethernet interface . eth0    only
> one external ip, so i want use by umls .

you need to set up the host as a gateway for your "internal" traffic, so
that all the packet arriving from eth0 can be redirect in the proper way
to the internal network.
Please see:

>                  and if above is solved, we only have on problem . how to
> ssh umls from the external network exmaple internet  , i think we only can
> access ,so we must setup a ssh gate,
if you choose to redirct ssh traffic on a specific port for ssh you can
manage, via iptables, the traffic from outside to the specific uml
> is there a soft like that , users can login with a username
> password ,the ssh gate forward to the internal uml he can loged in .
if you prefere you can launch an uml system at the login of a specific
user, just by adding the following command to the .bash_profile of this

exec linux ubd0=... umid=mytest eth0=...

(obviously to customize the ... field). Rmember that the user must belong
to the uml-net group!


Stefano Melchior, GPG key = D52DF829 - <stefano.melchior@openlabs.it>
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