Updated 2/2/2025
The ip commands replace the depreciated ifconfig and route comands.
The man pages of the ip commands are terse.
References:
ip address
Link is another term for a network interface.
To bring an interface up or down:
ip link set dev eth0 up
ip link set dev eth0 down
To manually set the address of an interface
ip address add 192.168.75.254/24 brd + dev eth0
brd - for broadcast
All Linux host have a routing table, whether they are a router or not.
The syntax is:
ip route [show] [dev interface]
The command "ip route" or "ip route show" will show the routes for all interfaces.
The older command:
route -n
Has a much better format with the parmaters in columns.
The ip route add command manually adds an entry to the host's routing table.
The basic form of the ip route add command is:
| destination | route | options | ||
|---|---|---|---|---|
| network/mask | dev | interface | [options] | |
| network/mask | via | gateway_ip | [options] | |
| network/mask | via | [options] | ||
The network/mask is a range of addresses. If you just specify an ip address for the network/mask, it will convert it to a network/mask.
The word "default" is a valid entry for the network/mask. If an ip destination address is not in one of the specified network/mask ranges, it takes this route.
For the word via, you can substitute gw.
To create a bridge:
ip link add name br0 type bridge
To add an interface to a bridge:
ip link set dev eth0 master br0
To remove an interface from a bridge:
ip link set dev eth0 nomaster
To view interfaces that are part of a bridge
bridge link
To assign an address to the bridge:
ip address add 192.168.75.254/25 brd + dev br0
To bring the bridge up:
ip link set dev br0 up
To add a wireless interface to a network bridge, you have to first assign the wireless interface to an access point or start an acess point with "hostap" [1].
There are special problems when bridging a wireless network interface. According to "ArchLinux Network Bridge, Section 3.1 Wireless interface on a bridge" [1], you have to first assign the wireless interface to an access point or start an access point with hostap. Otherwise it will not be added to bridge. However, there is catch. Most Access Points will reject frames that have source addresses that did not authenticate with the AP.
There are two methods to arround the catch [2][3]
References:
There are references that state that the Raspberry Pi wireless network adapter (wlan0) does not have the necessary registers and addr4 to support bridges.
Is this true or is the AP Authenification blocking the Raspberry Pi?
References:
