RHEL 802.1q / VLAN Tagging

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Contents

Overview

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

  • The "native VLAN" (in this example, VLAN 825). Frames for the native VLAN are not tagged, so no special configuration has to be performed for this VLAN. The bond0 interface is on the native VLAN 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

Procedure

Note: Once your network administrator enables 802.1q on the switch, your system may "fall off" the network if its network interface is not on the native VLAN (if applicable), as the host 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 VLAN 1100.
# vconfig add bond0 1100
  • Configure the VLAN device.
# 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-bond0.1100

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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