pfSense packer box
Create a pfSense box with Packer
Download ISO manually
As packer is not able to download gzipped ISO files directly, you have to download it manually and extract it. Then customize the pfsense.json file so packer could find the ISO file locally.
http://fleximus.org/mirror/pfsense/downloads/pfSense-LiveCD-2.1-RELEASE-i386.iso.gz
Create box
packer build -only=virtualbox-iso pfsense.json