M.I.T = Multimedia IT dept.

** First, we need to setup various VLAN interfaces, following my previous post as below.
http://my.opera.com/chenghan/blog/show.dml/10940431

** Second, install and configure DHCP server
$ sudo apt-get install dhcp3-server
$ sudo vi /etc/dhcp3/dhcpd.conf
INTERFACES="vlan149 vlan159";
** note: static addresses are needed for DHCP server interfaces!!

** Startup the DHCP server. Please check /var/log/syslog if startup failed
sudo service dhcp3-server start

==> OKAY, now any DHCP request from different VLANs could be processed normally!
==> note: since VLAN interfaces are configured, the switch port which DHCP server is connected should be marked as "tagged" with 802.1Q VID header!

REFERENCES:
http://140.115.236.9/xms/forum/show.php?id=14309
http://ubuntuforums.org/showthread.php?t=74925&highlight=dhcp3-server