> Mark,
> 
> Can I just check what I think you're getting at here. You have one
> ethernet LAN on which there are:
>   - machines on the 10.0.0.0 network which aren't sposed to see the
>     internet
>   - a router that receives packets destined for the 203.47.28.xx/xx
>     network (are there other 203.47.28.xx machines on the network?)
>   - a machine on 10.0.0.154 that you want to have a 203.47.28.148
>     address, accessible by both internal clients on one IP and the
>     internet on the external IP
> 
> Is this correct?
> 
> > The internal LAN subnet is 10.0.0.0/255.255.255.0.  I want internal 
> > clients to be able to see the machine via 10.0.0.154.  With the alias 
> > IP, 203.47.28.148, I want external clients on the internet to see the 
> > machine.  
> 
> Does your router already route all traffic on 203.47.28.148 to that
> network/machine? You can have two subnets on the same physical
> network but its not generally regarded as secure.
> 
> > Once I've configured the virtual address using eth0:1, what route do I 
> > need to add to allow packets destined for the internet to be routed 
> > through our router which is 203.47.28.150.  I've been adding the 
> > default gateway using the command below.
> > 
> > route add default gw 203.47.28.150
> 
> If the eth0 device has ip 10.0.0.154/255.255.255.0 then there
> *should* automatically be entered a route equivalent to:
>   route add -net 10.0.0.0 netmask 255.255.255.0 dev eth0
>  
> This with the default gateway above, should be all you need in the
> way of routing. What does your routing table look like at the
> moment? 
> 
> > However, due to my lack of experience in this, I think the internal 
> > packets are also trying to be routed via the router.
> 
> From the machine, run traceroute to an internal machine and
> this will tell you if its hitting the router or not. 
> 
> > I would assume 
> > one gateway should be defined for the alias (eth0:1) and not one for 
> > the internal IP (eth0) so that packets destined for the internet go 
> > through the gateway and all packets for the 10.0.0.0/255.255.255.0 are 
> > left alone.
> 
> On your routing table, you specify that all packets for 10.0.0.0 are
> just pumped out eth0 with no gateway, and all other packets (ie,
> your default gw) goes out eth0 with gateway 203.47.28.150 (your
> router).
> 
> If you have this alias setup and you can ping yourself at
> 203.x.x.148, and the routing table looks good, then it is most
> likely the router that needs reconfiguring. If its a cisco one, I
> can help. :-)
> 
> Cheers,
> 
> Bernard.

Yeah what Bernard said =]

.Chris

