DHCP helper-address configuration tool

Our DHCP helper specifications tends to drift towards complete inaccuracy over time. I have created a simple PHP script that can generate the necessary configuration commands for the HP switches to get things in sync.

The general principle is that we only specify DHCP helper addresses on the devices that are the route-point for the network in question. So only networks routed in DC by dc-cs1 and dc-cs2 have helpers specified on those devices. Assuming that networks are routed in a VRRP redundant pair, we must ensure that the helper information is identical on each of the devices participating in the VRRP group.

The PHP files are located in our ST attachments directory (they were created as a direct result of a work item):

• https://www.cs.uwaterloo.ca/cscf/internal/edocs/rtattach/73626/

The main command is "dhcp-helpers.php", with configuration files commands.php (the HP-specific commands required) and vlans.php (defines the vlans and helpers). Copy these three files to any system running PHP5 (specifically:

$ php --version
PHP 5.2.6-3ubuntu4.5 with Suhosin-Patch 0.9.6.2 (cli) (built: Jan  6 2010 22:41 
Copyright (c) 1997-2008 The PHP Group
Zend Engine v2.2.0, Copyright (c) 1998-2008 Zend Technologies

php dhcp-helpers.php help

A version of this command for the NetScreen firewall will be developed in due course.