網路原理(一) Section 2.1

kernel
核心
The portion of the OS that interacts directly with computer hardware is known as the kernel.

shell
The portion that interfaces with applications and the user is known as the shell.

Command-line interface
例如Windows的cmd

Graphical user interface (GUI)
圖形使用者介面

Cisco IOS
Cisco Internetwork Operating System

Firmware
韌體
The operating system on home routers is usually called firmware

Console Out-of-band
This is a physical management port that provides out-of-band access to a Cisco device.

SSH
Secure Shell (SSH) – SSH is a method for remotely establishing a secure CLI connection through a virtual interface, over a network. Unlike a console connection, SSH connections require active networking services on the device including an active interface configured with an address.

Telnet
Telnet is an insecure method of remotely establishing a CLI session through a virtual interface, over a network. Unlike SSH, Telnet does not provide a securely encrypted connection. User authentication, passwords, and commands are sent over the network in plaintext.

Auxiliary port (AUX)
輔助阜
Some devices, such as routers, may also support a legacy auxiliary port that was used to establish a CLI session remotely using a modem.

PuTTY ; Tera Term ; SecureCRT ; OS X Terminal
terminal emulation programs available for connecting to a networking device either by a serial connection over a console port or by a SSH/Telnet connection.

Cisco IOS modes
As a security feature, the Cisco IOS software separates management access into the following two command modes

User EXEC mode
This mode has limited capabilities but is useful for basic operations.

Privileged EXEC mode
To execute configuration commands, a network administrator must access privileged EXEC mode.

Global Configuration Mode
Higher configuration modes, like global configuration mode, can only be reached from privileged EXEC mode.

Line configuration mode
Used to configure console, SSH, Telnet, or AUX access.

Interface configuration mode
Used to configure a switch port or router network interface.

enable command ; disable command ; exit command ; end command
Key combination - Ctrl+Z
各種指令

Context-Sensitve Help
Context-sensitive help enables you to quickly find which commands are available in each command mode, which commands start with specific characters or group of characters, and which arguments and keywords are available to particular commands. To access context-sensitive help, simply enter a question mark, ?, at the CLI.

Command Syntax Check
Command syntax check verifies that a valid command was entered by the user.

CLI Hot Keys and Shortcuts
熱鍵和捷徑

Hostnames
本機名稱