How to Configure Network Bridge in CentOS/RHEL 7 using nmcli command
A Network Bridge is a link-layer device that forwards traffic between networks based on MAC addresses. It learns what hosts are connected to each network, builds a table of MAC addresses then makes a packet forwarding decision based on that table. A software bridge can be used in a Linux environment to emulate a hardware bridge. The most common application for software bridge is in a virtualized application for sharing a hardware NIC among one or more virtual NICs.
Let now show you how to create a Network Bridge in RHEL 7.0 using the nmcli command. Run ‘nmcli con show’ to check the current connection configuration. currently I don’t have any bridge configured in this system.
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Check the currently available interfaces for creating the Network Bridge. run ‘ip link’ command to see the available NIC interfaces in the system. Here I am using eno33554992 & eno50332216 to create bridge br0.
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Run the following command to create a bridge.
# nmcli con add type bridge con-name br0 ifname br0
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Now Bridge interface is created, lets add the Slave devices to this bridge interface using the following command.
# nmcli con add type bridge-slave con-name br0-port1 ifname eno33554992 master br0
# nmcli con add type bridge-slave con-name br0-port2 ifname eno50332216 master br0
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Now the bridge is ready let us check the configuration using the following command.
# brctl show
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Also we could check the connections information using ‘nmcli con show’. This would show us the bridge and slave interface connections information.
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Lets assign IP address to this Bridge for external communication.
# nmcli con mod br0 ipv4.addresses "192.168.1.200/24 192.168.1.1"
# nmcli con mod br0 ipv4.method manual
To view more information and setting on br0 bridge:
# nmcli con show br0
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Let’s enable the connection and check the IP address information. use the following command to enable the bridge br0.
# nmcli con up br0
‘ip add show br0’ will show the IP address associated with br0 bridge.
# ip add show
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