Autoinstallation Overview

Autoinstallation provides automatic configuration for a new device that you connect to the network and turn on, or for a device configured for autoinstallation. The autoinstallation process begins anytime a device is powered on and cannot locate a valid configuration file in the CompactFlash card. Typically, a configuration file is unavailable when a device is powered on for the first time, or if the configuration file is deleted from the CompactFlash card. The autoinstallation feature enables you to deploy multiple devices from a central location in the network.

For the autoinstallation process to work, you must store one or more host-specific or default configuration files on a configuration server in the network and have a service available—typically Dynamic Host Configuration Protocol (DHCP)—to assign an IP address to the device.

Autoinstallation takes place automatically when you connect an Ethernet or serial port on a new J Series or SRX Series device to the network and power on the device. To simplify the process, you can explicitly enable autoinstallation on a device and specify a configuration server, an autoinstallation interface, and a protocol for IP address acquisition.

This overview contains the following topics:

• Supported Autoinstallation Interfaces and Protocols
• Typical Autoinstallation Process on a New Device

Supported Autoinstallation Interfaces and Protocols

Before autoinstallation on a device can take place, the device must acquire an IP address. The protocol or protocols you choose for IP address acquisition determine the device interface to connect to the network for autoinstallation. The device detects the connected interface and requests an IP address with a protocol appropriate for the interface. Autoinstallation is supported over an Ethernet LAN interface or a serial LAN or WAN interface. Table 46 lists the protocols that the device can use on these interfaces for IP address acquisition.

Table 46: Interfaces and Protocols for IP Address Acqusition During Autoinstallation

If the server with the autoinstallation configuration file is not on the same LAN segment as the new device, or if a specific device is required by the network, you must configure an intermediate device directly attached to the new device, through which the new device can send Trivial File Transfer Protocol (TFTP), BOOTP, and Domain Name System (DNS) requests. In this case, you specify the IP address of the intermediate device as the location to receive TFTP requests for autoinstallation.

Typical Autoinstallation Process on a New Device

When a device is powered on for the first time, it performs the following autoinstallation tasks:

1. The new device sends out DHCP, BOOTP, RARP, or SLARP requests on each connected interface simultaneously to obtain an IP address.

   If a DHCP server responds, it provides the device with some or all of the following information:

   • An IP address and subnet mask for the autoinstallation interface.
   • The location of the TFTP (typically), Hypertext Transfer Protocol (HTTP), or FTP server on which the configuration file is stored.
   • The name of the configuration file to be requested from the TFTP server.
   • The IP address or hostname of the TFTP server.

     If the DHCP server provides only the hostname, a DNS server must be available on the network to resolve the name to an IP address.

   • The IP address of an intermediate device if the configuration server is on a different LAN segment from the new device.
2. After the new device acquires an IP address, the autoinstallation process on the device attempts to download a configuration file in the following ways:
   1. If the DHCP server specifies the host-specific configuration file (boot file) hostname.conf, the device uses that filename in the TFTP server request. (In the filename, hostname is the hostname of the new device.) The autoinstallation process on the new device makes three unicast TFTP requests for hostname.conf. If these attempts fail, the device broadcasts three requests to any available TFTP server for the file.
   2. If the new device cannot locate hostname.conf, the autoinstallation process unicasts or broadcasts TFTP requests for a default device configuration file called network.conf, which contains hostname-to-IP address mapping information, to attempt to find its hostname.
   3. If network.conf contains no hostname entry for the new device, the autoinstallation process sends out a DNS request and attempts to resolve the new device's IP address to a hostname.
   4. If the new device can determine its hostname, it sends a TFTP request for the hostname.conf file.
   5. If the new device is unable to map its IP address to a hostname, it sends TFTP requests for the default configuration file router.conf.
3. After the new device locates a configuration file on a TFTP server, autoinstallation downloads the file, installs the file on the device, and commits the configuration.