Gary’s Weblog

Debian Linux VLAN musings

I am getting a network monitoring server ready. This server will need a direct connection to all of our subnets. This is not too hard because I can use multiple VLANs within one physical interface.

What was hard was finding authoritative documentation for VLANs on Debian. Maybe I was looking in the wrong places (google), I don’t know. It turns out it is a simple procedure. Finding the info and experimenting took all the effort.

First you install the “vlan” package so you will have the utilities needed to manipulate VLANs:

apt-get install vlan

Then you define your VLAN interfaces in /etc/network/interfaces like so:
auto vlan2
iface vlan2 inet static
vlan_raw_device eth0
address 192.168.22.20
netmask 255.255.255.0
network 192.168.22.0
broadcast 192.168.22.255
gateway 192.168.22.1


UPDATE:
Well that project crashed and burned. It turns out that I am limited by the switch. It is necessary to use port mirroring on the switch so that the monitoring server will get all the network traffic from the other servers. With the switch I have (HP 4104gl) you can only mirror ports that are on the same module as the monitoring port. The switch has four modules, with servers populating all four. So that restricts things quite a bit. Too much to make it worth it in fact.

At least I figured out that I don’t need to use VLANs for monitoring (it was a good learning experience though).

Thursday, May 10th, 2007 Filed under Technical |