$Id: FAQ,v 1.1.1.4 2003/10/14 08:09:37 sparq Exp $

If you have still unanswered questions after reading the HOWTO and the
FAQ, you have found a bug. Please report bugs to bridge@openrock.net
or buytenh@openrock.net.

Lennert Buytenhek



Questions that were Asked Frequently enough to get listed here
==============================================================



What does a bridge do?
----------------------
  A bridge transparently relays traffic between multiple network
  interfaces. In plain English this means that a bridge connects two
  or more physical ethernets together to form one bigger (logical)
  ethernet.


Is it protocol independent?
---------------------------
  Yes. The bridge knows nothing about protocols, it only sees ethernet
  frames. As such, the bridging functionality is protocol independent,
  and there should be no trouble relaying IPX, NetBEUI, IP, IPv6, etc.


How is this bridging stuff different from a so-called 'switch'?
---------------------------------------------------------------
  It isn't.


Why is your code better than a switch?
--------------------------------------
  It's more flexible. It allows you to have all kinds of bizarre port
  combinations for example (I have actually set up a bridging linux
  box with 1 100baseT and 5 10base2 ports in a production
  environment. A 10/100Mbit switch plus 5 media converters would have
  been way more expensive.)  Also, it allows you to set up multiple
  bridge port groups. And the standard linux network filtering can be
  applied to bridge forwarding (As of Feb 5 this is still a beta
  add-on patch, albeit a rock solid one.)

  <digress>
  At home, I have joined eth0,eth1,tap0 on my server together into one
  bridge (br0). My laptop connects to my server via plip (I haven't
  bought a PCMCIA network card yet). tap0 on my laptop is connected to
  tap0 on my server via the plip link. This way my laptop is
  transparently visible in my home network. No more mucking with proxy
  arp et al. It works great.
  </digress>


My bridge does not show up in traceroute!
-----------------------------------------
  It is supposed not to. The operation of a bridge is (supposed to be)
  fully transparent to the network, the networks that a bridge
  connects together are actually to be viewed as one big
  network. That's why the bridge does not show up in traceroute; the
  packets do not feel like they are crossing a subnet boundary.

  With routers, this is different. Routers are supposed to show up in
  traceroute, because...... [FINISH ME]


Are there plans for MAC address filtering?
------------------------------------------
  No.

  However, there is IP filtering (as an add-on patch), maybe this is
  what you want? You can find the patch in patches/, filename
  bridge-ipchains-*.diff. Apply it on top of the ordinary patch. See
  the file FIREWALL in the distribution for more details.
