Chapter 1,2,3

Telnet

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.

Secure Shell (SSH)

A UNIX-based command interface and protocol for securely accessing a remote computer.

Internet

A global network connecting millions of computers, making it possible to exchange information.

Storage Area Network (SAN)

A network infrastructure designed to support file servers and provide data storage, retrieval, and replication.

Wide Area Network (WAN)

A network infrastructure that provides access to other networks over a wide geographical area, which is typically owned and managed by a telecommunications service provider.

Local Area Network (LAN)

A network infrastructure that provides access to users and end devices in a small geographical area, which is typically an enterprise, home, or small business network owned and managed by an individual or IT department.

Metropolitan Area Network (MAN)

A network infrastructure that spans a physical area larger than a LAN but smaller than a WAN (e.g., a city). MANs are typically operated by a single entity such as a large organization.

Extranet

A private electronic network that links a company with its suppliers and customers

Network Interface Card (NIC)

An expansion card that enables a computer to connect other computers or to a cable modem to facilitate a high-speed Internet connection.

Availability

Data availability means having the assurance of timely and reliable access to data services for authorized users.

Confidentiality

Data confidentiality means that only the intended and authorized recipients can access and read data.

Integrity

Data integrity means having the assurance that the information has not been altered in transmission, from origin to destination.

DSL

Digital Subscriber Lines provide a high bandwidth, always on, connection to the Internet. DSL runs over a telephone line. In general, small office and home office users connect using Asymmetrical DSL (ADSL), which means that the download speed is faster than the upload speed.

HTTP

Hypertext Transfer Protocol

IP

Internet Protocol

Dedicated Leased Line

Leased lines are actually reserved circuits within the service provider's network that connect geographically separated offices for private voice and/or data networking. The circuits are typically rented at a monthly or yearly rate. They can be expensive.

Wireless LAN (WLAN)

Similar to a LAN but wirelessly interconnects users and end points in a small geographical area.

shell

The component of the operating software that provides the user interface

network portion

The left-most part of the address that indicates which network the IP address is a member. All devices on the same network will have the same network portion of the address.

host portion

The remaining part of the address that identifies a specific device on the network. The host portion is unique for each device on the network.

Intrusion prevention systems (IPS)

These are used to identify fast-spreading threats, such as zero-day or zero-hour attacks.

Antivirus and antispyware

These are used to protect end devices from becoming infected with malicious software.

Dedicated firewall systems

These are used to provide more advanced firewall capabilities that can filter large amounts of traffic with more granularity.

TCP

Transmission Control Protocol - provides reliable, ordered, and error-checked delivery of a stream of packets on the internet. TCP is tightly linked with IP and usually seen as TCP/IP in writing.

cable

Typically offered by cable television service providers, the Internet data signal is carried on the same cable that delivers cable television. It provides a high bandwidth, always on, connection to the Internet.

Internet Service Provider (ISP)

a company that provides access to the internet for a monthly fee

Ethernet

a physical and data layer technology for LAN networking

Intranet

a private connection of LANs and WANs that belongs to an organization, and is designed to be accessible only by the members and employees of the organization, or others with authorization.

Access Control List (ACL)

these are used to further filter access and traffic forwarding.