12. Appendix; Transmission Using Ipsec; Encryption And Authentication By Ipsec - Ricoh M C251FW User Manual

12. Appendix

This chapter describes the machine specifications and consumables.

Transmission Using IPsec

For securer communications, this machine supports the IPsec protocol. When applied, IPsec encrypts
data packets at the network layer using shared key encryption. The machine uses encryption key
exchange to create a shared key for both sender and receiver. To achieve even higher security, you can
also renew the shared key on a validity period basis.
• IPsec is not applied to data obtained through DHCP or DNS.
• IPsec compatible operating systems are Windows 8.1 or later, Windows Server 2012 or later,
macOS 10.13 or later, Red Hat Enterprise Linux 7.3, 7.4, 7.5, and 7.6. However, some setting
items are not supported depending on the operating system. Make sure the IPsec settings you
specify are consistent with the operating system's IPsec settings.
• If you cannot access Web Image Monitor due to IPsec configuration problems, disable IPsec under
[Administrator Tools] on the control panel, and then access Web Image Monitor.
• For details about specifying the IPsec settings using Web Image Monitor, see page 312
"Configuring the IPsec Settings".
• For details about enabling and disabling IPsec using the control panel, see page 251
"Administrator Tools Settings".

Encryption and Authentication by IPsec

IPsec consists of two main functions: the encryption function, which ensures the confidentiality of data,
and the authentication function, which verifies the sender of the data and the data's integrity. This
machine's IPsec function supports two security protocols: the ESP protocol, which enables both of the
IPsec functions at the same time, and the AH protocol, which enables only the authentication function.
ESP Protocol
The ESP protocol provides secure transmission through both encryption and authentication. This
protocol does not provide header authentication.
• For successful encryption, both the sender and receiver must specify the same encryption
algorithm and encryption key. The encryption algorithm and encryption key are specified
automatically.
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