[TriLUG] using a Linux box as a pass-through filter

[Aaron S. Joyner]

Dan Monjar wrote:

> Jason Tower wrote:
>
>>
>> you can do this with linux, but you can do it a lot easier with 
>> openbsd (google for 'openbsd transparent firewall').  i have this 
>> exact setup running on a client's colo rack, the firewall is 
>> literally invisible - it has no ip address.  as such, you can't ssh 
>> in to manage it, so i run it headless and have to ssh to another box, 
>> where i login and use minicom to communicate with it via a serial 
>> port.  works great.
>>
>> jason
>
>
> Beautiful... OpenBSD is preferred, I use it for a couple of servers 
> already.  Thanks for the lead.
>
Another good tip to help narrow your googling, is that this is typically 
referred to as a "bridging firewall".  You're going to assign your two 
interfaces in OpenBSD to a single, bridge interface (usually named 
br0).  As a pointers into the OpenBSD docs, check here:
http://www.openbsd.org/faq/faq6.html#Bridge

Aaron S. Joyner