[X4U] Mac mini as an Internet Gateway.

[Stroller]

On Dec 14, 2005, at 1:07 pm, Robert Tillyard wrote:

> I'm planning on using Mac OS X Server 10.4 on a Mac mini to handle 
> e-mail/web proxy for a group of computers (Mac and Windows). Our ISP 
> gives us a router with a fixed public IP Address.
>
> I'm currently using a UNIX box with two network cards to do this, one 
> card has the public IP address and the other is our internal network.
>
> 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 to do this with.

I'm not sure what you're trying to do here...

If you want to use the Mac Mini as a (NAT) router then it won't work. I 
looked into this fairly extensively - admittedly under Linux rather 
than Mac OS X, but it shouldn't make any difference - trying to route 
through a single physical interface causes packet collisions and 
slowdowns & all manner of Bad Things. It might work _extremely slowly_ 
but people who know far more than me report that it's such a terrible 
idea you shouldn't even try - maybe you can find a USB Ethernet adaptor 
with Mac drivers instead.

On the other hand, if you just want to have a little web / email server 
that has two IP addresses then this is no problem at all. You don't 
even have to use `ifconfig` - just go into System Preferences > Network 
and choose "Show: Network Port Configurations" from the dropdown (10.3 
here); add a new configuration called "Built-on Ethernet - wibble" and 
assign it the port "Built-in Ethernet". You will find you're able to 
check both configurations to make them simultaneously active, and can 
configure each one separately as normal.

Stroller.