Server Fault is a question and answer site for system and network administrators. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I'm creating bridge network on Ubuntu 9.04(server)

I set up following configuration file


auto lo
iface lo inet loopback

auto eth0
iface eth0 inet manual

auto br0
iface br0 inet static
bridge_ports eth0
bridge_fd 9
bridge_hello 2
bridge_maxage 12
bridge_stp off

I don't know this parameter meenings bridge_fd,bridge_hello,bridge_maxage,bridge_stp

share|improve this question
up vote 14 down vote accepted

This is the forwarding delay for interfaces joining the bridge. It's how long it'll be before the interface will be able to do anything. . During this time the bridge will be discovering other bridges and checking that no loops are created. For a better description and the reason for it you need to read up on spanning tree protocol.

share|improve this answer
"how long it'll be" in seconds – rakslice Dec 20 '11 at 22:39

They correspond to brctl settings. Look at man brctl.

brctl(8) can be used for configuring certain spanning tree protocol parameters. For an explanation of these parameters, see the IEEE 802.1d specification. The default values should be just fine. If you don’t know what these parameters mean, you probably won’t feel the desire to tweak them.

share|improve this answer
A slightly better resource is the bridge-utils-interfaces manual page. – Wichert Akkerman Mar 30 '12 at 7:53

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.