HP JetAdvantage Security Manager 10 Device E-LTU Manual do Utilizador descarregar pdf (Página 98)

TFTP Configuration File

BOOTP and TFTP provide a method to configure HP print devices. When the HP device is turned on,

a BOOTP request is sent to the server to initiate the configuration, which typically uses a TFTP

configuration file. Select the check box to assess whether a TFTP configuration file is used on the

device and then whether to enable or disable its use. Note: The TFTP protocol does not support

authentication or encryption. Use of this protocol might introduce a security risk.

Trivial File Transfer Protocol (TFTP) is a simple file transfer protocol described in RFC 1350. It was

designed to be a lightweight, minimally featured protocol implemented over UDP Port 69, but can be

implemented for any transport protocol. Data transfer is initiated on Port 69, but the data transfer

ports are chosen independently by the sender and receiver during initialization of the connection. The

ports are chosen at random according to the parameters of the networking stack, typically from the

range of ephemeral ports (a predefined range of ports).

TFTP lacks most of the features of FTP. Unlike FTP, TFTP is not an interactive protocol, can’t list

directories or contents, and lacks authentication. TFTP only reads from or writes to a remote server.

TFTP has historically been used in Jet Direct products for transferring upgrade images across a

network from a host computer to Jetdirect flash. It has also been used for transferring configuration

information via a BOOTP request. To configure Jetdirect via BOOTP/TFTP, a :T144 entry in the

Bootptab file pointing to the TFTP configuration file would be required. A TFTP configuration file can

contain JetDirect configuration items such as administrative passwords, printing and discovery

protocol enabling/disabling, TCP/IP configuration, and SNMP configuration, to name a few.

Because TFTP provides no means for validating the identity of a computer requesting file transfers, the

security of TFTP can be a major concern. If TFTP is not configured correctly, a rogue machine could

become a legal machine on the network. A common way for someone to look for machines with TFTP

configured incorrectly is to perform directed broadcasts of TFTP Request packets to different networks

and see which machines respond. If BOOTP is being used in the environment to assign printer

addresses and configure printer settings, the TFTP Configuration File setting will need to be enabled.

For most printer firmware, HP Web Jetadmin opens up a port 9100 connection and sends the .rfu file

as a print job. For HP Jetdirect firmware, HP Web Jetadmin uses the TFTP protocol to complete the

upgrade. It is recommended to disable TFTP if not in use for device configuration and disable when

not in use for firmware upgrades.

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HP JetAdvantage Security Manager 10 Device E-LTU Manual do Utilizador Página 98