Linux allows binding multiple network interfaces into a single channel/NIC using special kernel module called bonding. According to official bonding documentation, The Linux bonding driver provides a method for aggregating multiple network interfaces into a single logical "bonded" interface. The behavior of the bonded interfaces depends upon the mode; generally speaking, modes provide either hot standby or load balancing services. Additionally, link integrity monitoring may be performed.

Setting up bounding is easy with RHEL v4.0. Red Hat Linux stores network configuration in /etc/sysconfig/network-scripts/ directory. First, you need to create bond0 config file:

# vi /etc/sysconfig/network-scripts/ifcfg-bond0

Append following lines to it:

DEVICE=bond0
IPADDR=192.168.1.20
NETWORK=192.168.1.0
NETMASK=255.255.255.0
USERCTL=no
BOOTPROTO=none
ONBOOT=yes

Replace above IP address with your actual IP address. Save file and exit to shell prompt. Now open the configuration files for eth0 and eth1 in the same directory using the vi text editor and make sure file read as follows for eth0 interface:

# cat /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE=eth0
USERCTL=no
ONBOOT=yes
MASTER=bond0
SLAVE=yes
BOOTPROTO=none

Repeat the same for the ifcfg-eth1 file, of course, set the DEVICE to eth1. Then, make sure that the following two lines are added to either /etc/modprobe.conf or /etc/modules.conf (see this page or also this page for more information):

alias bond0 bonding
options bond0 mode=1 miimon=100

Then load the bonding module:

# modprobe bonding

Restart networking service in order to bring up bond0 interface:

# service network restart

Verify everything is working:

# less /proc/net/bonding/bond0
Bonding Mode: load balancing (round-robin)
MII Status: up
MII Polling Interval (ms): 0
Up Delay (ms): 0
Down Delay (ms): 0

Slave Interface: eth0
MII Status: up
Link Failure Count: 0
Permanent HW addr: 00:0c:29:c6:be:59

Slave Interface: eth1
MII Status: up
Link Failure Count: 0
Permanent HW addr: 00:0c:29:c6:be:63

If you found this useful, here's more on the same topic(s) in our blog:

• AIX: Delete multiple default gateways
• Install Python version 3 on Red Hat / CentOS
• Prune old Docker data
• Setting up a bonded network interface on RHEL 7
• How to tie a system to a specific update of Red Hat Enterprise Linux