RHEL 802.1q / VLAN Tagging

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Contents

Overview

In this example on a RHEL 5 system, I take an interface that is bonded with mode 6 (balance-alb) and enable 802.1q, or "VLAN tagging." The bonded interface will be a member of two VLANs:

  • VLAN 825 with IP address 10.216.16.48 and netmask 255.255.240.0
  • VLAN 1100 with IP address 10.216.225.1 and netmask 255.255.240.0

The current interface is bond0 with an IP address of 10.216.16.48 and netmask of 255.255.240.0.

Procedure

Note: Once your network administrator enables 802.1q on the switch, your system will appear to "fall off" the network. It won't know how to handle VLAN tagged-frames until you perform the below steps.

Current boot environment

The following steps will enable 802.1q for your current session. The configuration will not be preserved across reboots.

  • Enable the 8021q kernel module.
# modprobe 8021q
  • Create a VLAN device on the bond0 interface for both VLANs.
# vconfig add bond0 825
# vconfig add bond0 1100
  • Configure the VLAN devices.
# ifconfig bond0.825 10.216.16.48 255.255.240.0 up
# ifconfig bond0.1100 10.216.225.1 255.255.240.0 up

Preserving the changes across system boots

To preserve the 802.1 configuration changes across reboots, create appropriate /etc/sysconfig/network-scripts files.

e.g., /etc/sysconfig/network-scripts/ifcfg-bond0.825

DEVICE=bond0.825
IPADDR=10.216.16.49
NETMASK=255.255.240.0
GATEWAY=10.216.16.1
ONBOOT=yes
BOOTPROTO=static
USERCTL=no
VLAN=yes

e.g., /etc/sysconfig/network-scripts/ifcfg-bond0.1100

DEVICE=bond0.1100
IPADDR=10.216.225.1
NETMASK=255.255.240.0
ONBOOT=yes
BOOTPROTO=static
USERCTL=no
VLAN=yes
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