[X4U] Mac mini as an Internet Gateway.

[Ted Burton]

At 1:07 PM +0000 on 12/14/05, Robert Tillyard 
spoke about [X4U] Mac mini as an Internet 
Gateway. thusly:

>Is it feasible to so this on a Mac mini with a 
>single ethernet port? I'm wondering if I can use 
>ifconfig to 'alias' the external IP address to 
>the same ethernet port that has our internal 
>address. I know it would be better to have two 
>network cards but I don't have a G5 or XServe 
>spare todo this with.

Yes. I have run an inside server with one 
Ethernet port, but as I had it set up the router 
handled the NAT, not the computer. The server was 
connected to the router as were all the other 
boxes in those places. In the larger shop we had 
switches -- for that matter here at the mediation 
SOHO I have a router and multiple cables into it. 
I no longer have an in-house server because 
cableone.net refuses to provide an MX20 for an 
in-house MX10. So I let them provide both.

When I did this in each of two earlier 
incarnations of mine, figuratively speaking of 
course, the equivalent to the mini had an inside 
IP number which I assigned manually, and it 
functioned as a server of files and a mail server 
running Eudora Internet Mail Server.  I 
configured the router to pass incoming e-mail to 
that inside computer by the fixed IP number, and 
configured EIMS to send via the router. Other 
computers in these shops were told to use the 
inside IP number for the server as their mail 
server.

With two Ethernet cards in a Unix box you were in 
essence having a second NAT after the router did 
NAT.

If you want to do NAT twice, you can always get 
IPNetRouterX and run it on the mini to do a 192 
to 10 or something NÅT.