Posts Tagged ‘VLAN’

Sysconfig ifcfg scripts and VLAN sub-interfaces

Monday, August 16th, 2010

If you are using the ifcfg scripts in /etc/sysconfig/network-scripts to bring up VLAN sub-interfaces on a NIC and you are getting messages such as:

Bringing up interface eth0.200: Device eth0.200 does not seem to be present, delaying initialization.

instead of

Bringing up interface eth0.200: Added VLAN with VID == 200 to IF -:eth0:-

as you would expect, then make sure that you have the vconfig RPM installed.

Changing the MAC address of a VLAN interface in Mikrotik RouterOS

Saturday, July 3rd, 2010

Do you want to change the MAC address of a VLAN interface in Mikrotik RouterOS? Are you baffled by the fact that although the VLAN interface has a MAC address property inherited from the parent Ethernet interface, it isn’t editable?

Well, you’re in luck, it isn’t actually impossible to give your VLAN interface a different MAC address to it’s parent interface, you just have to go about it in a somewhat roundabout way by making what is effectively a virtual Ethernet interface and bridging it to the VLAN interface. You then add your layer 3 IP functions to the bridge interface instead of to the VLAN interface.

First, you need to create a bridge and give it a name, then add the VLAN interface who’s MAC address you want to change to the bridge as a port. Finally, set the “auto-mac” property on the bridge to “no” and then change “admin-mac” property for the bridge to be whatever you want your new MAC address to be

/interface bridge add name=newmac disabled=no auto-mac=no admin-mac=”00:00:00:00:00:00″
/interface bridge port add bridge=newmac interface=vlan1