Brctl Command

2014-01-22 393 words One minute

Contents

Bridges

View

To view the current bridges, use the following command on a SSH/Telnet terminal:

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 brctl show

The command will then output a bridge name (Often br0 or br1), bridge ID (Used to uniquely specify the bridge), and the current settings for STP (Spanning Tree Protocol). The output wil be formated similar to this:

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 bridge name     bridge id               STP enabled  
 br0             8000.001217318d3e       yes

Add

A bridge can be added using the following command, with being replaced with the name of the bridge being replaced.

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 brctl addbr <name>

Delete

Where name is the user specified name of the bridge. To delete a bridge, one would use

brctl delbr

Interfaces

Although the preceding commands simply create an instance of a bridge, in order to use them, one must add interfaces to a bridge. The bridge “br0” is standard bridge on DD-WRT.

Show

In order to show the current interfaces that are members of a bridge, we use a command similar to the “show” command:

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 brctl showbr br0 (for V23SP2: brctl showstp br0)

This would generate output similar to the following:

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 br0  
  bridge id              8000.001217318d3e  
  designated root        8000.001217318d3e  
  root port                 0                    path cost                  0  
  max age                  20.00                 bridge max age            20.00  
  hello time                2.00                 bridge hello time          2.00  
  forward delay             0.00                 bridge forward delay       0.00  
  ageing time              42.30                 gc interval                4.00  
  hello timer               1.28                 tcn timer                  0.00  
  topology change timer     0.00                 gc timer                   2.02  
 flags  
  
 vlan0 (1)  
  port id                8001                    state                   forwarding  
  designated root        8000.001217318d3e       path cost                100  
  designated bridge      8000.001217318d3e       message age timer          0.00  
  designated port        8001                    forward delay timer        0.00  
  designated cost           0                    hold timer                 0.00  
  flags  
  
 eth1 (2)  
  port id                8002                    state                   forwarding  
  designated root        8000.001217318d3e       path cost                100  
  designated bridge      8000.001217318d3e       message age timer          0.00  
  designated port        8002                    forward delay timer        0.00  
  designated cost           0                    hold timer                 0.00  
  flags

Here we can see that the bridge contains two members, eth1 and vlan0.

Add

To add a interface to a bridge, the command syntax is

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 brctl addif <brname> <ifname>

Where is the existing bridge name, and ifname is the interface you want to add.

Remove

To remove a interface from a bridge, the syntax is very similar

brctl delif

Source:http://www.dd-wrt.com/wiki/index.php/Brctl_command