Guide - Part 6: Network Configuration Flashcards
What do the terms “interface,” “protocol,” and “service” mean in relation to computer networks?
An interface is any channel through which network data can flow. Hardware network interfaces are defined by physical
network connections, and virtual network interfaces are logical network connections that ride on top of hardware network connections. A protocol is a set of rules used to describe a specific type of network communication. Protocols are necessary for separate network devices to communicate properly. Finally, a network service (as it pertains to Network preferences) is the collection of settings that define a network connection.
What’s the purpose of Internet Protocol v4 (IPv4) addresses and subnet masks?
The Internet Protocol (IP) address identifies the location of a specific network device. IP addresses are the primary identification used by the Internet protocol suite TCP/IP for both local area and wide area networks. Subnet masks are used by network devices to identify their local network range and to determine whether outgoing data is destined for a network device on the LAN.
How does IPv4 addressing differ from IPv6 addressing?
Most common IP addresses and subnet masks share the same IPv4 formatting. An IPv4 address is a 32-bit number represented in four groups of three-digit numbers, known as octets, separated by periods. Each octet has a value between 0 and 255. An IPv6 address is a 128-bit number that’s presented in eight groups of four-digit hexadecimal numbers separated by colons. This allows for a huge range of addresses, and as a result IPv6 addressing essentially includes subnet information.
How does the IP use the MAC address to send messages
between computers on a local area network (LAN)?
If a network device needs to send data to another network device on the same LAN, it addresses the outgoing packets based on the destination device’s MAC address.
How does the IP transfer messages between computers over a wide area network (WAN)?
A network client uses the subnet mask to determine whether the destination IP address is on the LAN. If the destination IP address isn’t on the LAN, it’s assumed that the destination address is on another network, and the client sends the data to the IP address of the local network router. The network router then sends the data, via a WAN connection, to another router that it thinks is closer to the destination. This continues across WAN connections from router to router until the data reaches its destination.
How is the Domain Name Service (DNS) used to facilitate network naming?
The DNS is used to translate host names to IP addresses via forward lookups and translate IP addresses to host names via reverse lookups. DNS is architected as a hierarchy of worldwide domain servers. Local DNS servers provide name resolution and possibly host names for local clients. These local DNS servers connect to DNS servers higher in the DNS hierarchy to resolve both unknown host names and host local domain names.
What’s used to identify a Wi-Fi network?
A Service Set Identifier, or SSID, is used to identify a Wi-Fi network name and associated configuration.
Which Wi-Fi authentication protocols are supported by OS X?
OS X supports authenticated Wi-Fi via the following authentication protocols: WEP, WPA/WPA2 Personal, and WPA/ WPA2 Enterprise, which includes support for 802.1X authentication.
How can an OS X system automatically connect to a Wi-Fi network?
A new OS X system can automatically connect only to Wi-Fi networks that have no standard authentication mechanism, known as an “open network.” However, a configured OS X system can automatically reconnect to authenticated Wi-Fi networks, provided that the appropriate information was saved to the Keychain system.
Through which mechanism can a standard user configure Wi- Fi settings?
A standard user can connect to any non-WPA Enterprise Wi-Fi network via the Wi-Fi status menu. Because the system Keychain must be modified for WPA Enterprise connections, only an administrative user can establish these types of connections.
What’s a network location? Who can access network locations?
A network location is a saved state of Network preferences that contains all network interface settings. Only administrators can define network locations, but if more than one location exists, all users can switch between the various network locations via the Apple menu.
Which interfaces and protocols are supported by default in OS X?
OS X supports the following network interfaces and protocols:
• Ethernet IEEE 802.3 family of hardware network interface
standards
- Wireless (Wi-Fi) IEEE 802.11 family of hardware network interface standards
- FireWire IEEE 1394 bridged network interface
- Thunderbolt bridged network interface
- Bluetooth wireless hardware network interface
- USB connectivity via cellular network adapters or iOS devices with cellular network service
- Virtual private network (VPN) virtual network interface via the Point-to-Point Tunneling Protocol (PPTP)
- VPN virtual network interface via the Layer 2 Tunneling Protocol (L2TP) over Internet Protocol Security (IPSec)
- VPN virtual network interface via Cisco IPSec
• Point-to-Point Protocol over Ethernet (PPPoE) virtual
network interface
- 6 to 4 virtual network interface
- Virtual local area network (VLAN) virtual network interface via the IEEE 802.1Q standard
- Link Aggregation virtual network interface via the IEEE 802.3ad standard
- Transmission Control Protocol/Internet Protocol (TCP/IP), also known as the Internet protocol suite
- Dynamic Host Configuration Protocol (DHCP)
- Domain Name Service (DNS) protocol
• Network Basic Input/Output System (NetBIOS) and
Windows Internet Naming Service (WINS) protocols
• Authenticated Ethernet via the 802.1X protocol
What functionality does OS X support with the AppleTalk protocol?
AppleTalk works only with Mac OS X v10.5 or earlier.
How does network service order affect network connectivity?
The network service order list is used to determine the primary network service interface if there is more than one active service. All network traffic that isn’t better handled via local connection to an active network service interface is sent to the primary network service interface. So in most cases all WAN traffic, Internet traffic, and DNS resolution is sent through the primary network service interface.
In Network preferences, how can you tell which interface is
currently being used for network activities?
In Network preferences, all network service interfaces with a green status indicator are being used for network activities. However, again, all network traffic that isn’t better handled via a local connection is sent to the primary network service interface. The primary network service interface is the topmost active interface in the listing.
