How to configure switching between network interfaces?

[Chuck Swiger]

mstrickland16 at nc.rr.com wrote:
> How to configure switching between network interfaces?
> I would like to determine how, or if, the following can be accomplished with FreeBSD. 
> Configuration:
> A BSD box setup with 1 GbE NIC and a 4 port 10/100 NIC
> The GbE interface will have a static IP configured (192.168.10.x/24)
> Planned Implementation:
>   Along with possibly serving other data such as NFS or HTTP traffic, I would like the interfaces to work as a switch. The GbE interface is a fiber optic NIC which connects to the rest of the network 100 or so meters away. I plan to use the other 4 interfaces to attach hosts to my network. I would prefer all of my hosts to be on the same subnet if possible, otherwise I would just configure routing between the appropriate interfaces. My question then is: Can the interfaces be configured to function as a switch would, allowing the connected hosts to recieve DHCP and other traffic "routing" from the fiber optic interface via the FreeBSD box. I know that in a basic configuration, 2 interfaces on the same subnet are not a best practice and would required special routing information. I assume that somewhere this can be configured. A good shove in the right direction would be most appreciated.

You can configure the interfaces together as a bridge and FreeBSD will act as 
a "smart switch"-- see the bridge(4) manpage or the Handbook for more info.

Note that this configuration might make sense if you wanted to impose firewall 
rules to limit cross-segment traffic while still letting the client machines 
all be on one subnet.  Or you might divert all WWW traffic seen going by to a 
transparent proxy server.

But unless you plan to do something with this traffic like that-- if all you 
want to do is have a switch-- you'd otherwise be better off getting a 4-port 
gigabit Cu or Fibre switch then setting up a dedicated server for the task.

-- 
-Chuck