A small-form programmable pluggable device 80 is used to establish communication between a configurable “bare-metal” server 50 having no existing configuration software installed, and a provisioning server 60 capable of downloading software to the configurable server 50 to allow the configurable server 50 to be configured to perform a specific function. The pluggable device carries sufficient programming to access the required software 63 and deliver it to the configurable server 50. This allows the configurable server to be delivered to its end-user before configuration, and configuration to be performed by the network operator in situ, but without a site visit, by delivery and plug-in of the small-form device 80, which is typically of a suitable size to be mailed.