The cnPilot R200 and R201 support using DHCP options 66 out of the box, to pull down configuration from a TFTP/HTTP server. This mechanism can also be used to upgrade the firmware on these devices.
This auto-provisioning is enabled in the factory-default configuration of the device. It can be disabled by the administrator through a configuration update if necessary (under Administration->Provision).
While this mechanism is used for updating the configuration, it can also be used to update the firmware of the device by setting up a TFTP server with the new firmware, and pointing the AP to it using a config command. Multiple devices can be upgraded in parallel from the same DHCP and TFTP servers.
Setup
Auto provisioning is configured on a DHCP server by adding a DHCP option (#66) to specify the IP address of a server the device should use for pulling down its configuration.
For instance on TFTPD32 (a free TFTP/DHCP server) the following screenshot shows 192.168.20.50 setup as option 66 on its DHCP server.
The WAN port of the R200 and R201 is configured to be a DHCP client by default. When the R200/R201 is powered up, the AP will receive an IP address using DHCP over this port. When as part of that DHCP response it also sees the Option-66, the AP will use that as an indication to retrieve a configuration file from the specified TFTP server.
The normal mode of operation of the device is to try and retrieve a filename that is same as its Internet (WAN) MAC address. This address is on the label of the unit as well as the packaging the AP comes in, in upper-case without any separators (Eg: The filename should be something like 000456A1B2C3).
Use of MAC address as the filename is only the default setup on the cnPilot R200 and R201. The administrator can configure the AP with other macros (Eg: $(PN) to indicate the Product Name of “cnPilot R200”, $(IP) to indicate the IP address) and setup the filename that way.
Firmware Upgrade
It is also possible to update the firmware on the R200 and R201 using DHCP options. We do this by extending the config update feature and setting the Upgrade-Path configuration item on the TFTP server.
So for instance to have an AP with MAC address 000456A1B2C3 upgrade its firmware to R200-4.3-R3.bin, we create a file on the TFTP server, name it 000456A1B2C3 and add the following line into it:
DBID_UPGRADE_RULE=tftp://192.168.20.50/R200-4.3-R3.bin
The firmware file should be placed in the TFTP root directory of 192.168.20.50. Now when that AP is booted up, it would pull this file down as a configuration item, and read this line to see it needs to upgrade itself.
Disable use of Option-66
If option-66 was only being used to stage the access points, and in the field the administrator wishes to keep this disabled, that can be configured by including the following line in the configuration file that is downloaded to the AP:
DBID_PRV_OPTION66_ENABLED=0
The feature can also be disabled from the GUI of the R200/R201 APs, under Administration->Provision.
