Network Configurations (2.1, 2.5 and 2.6) Flashcards
Where is the data limited to travelling in the link/network interface layer?
The local area network
What is the link/network interface layer responsible for?
Putting frames in the physical network’s transmission media
What is the internet layer used for?
Addressing packets and routing them across the network
What does the transport layer do?
Shows how to send the packets (using protocols e.g. TCP and UDP)
What does the application layer contain?
All the protocols that perform higher-level functions
Define multicast address
A logical identifier for a group of hosts in a computer network
What is a classful mask?
Default subnet mask for a given class of IP addresses
What does classless inter-domain routing (CIDR) allow?
Borrowing some of the host bits and reassigning them to the network portion
What is a public (routable) IP?
Can be accessed over the Internet and is assigned to the network by an ISP
Describe a private (non-routable) IP, including the numbers it could start with.
Can by used by anyone at any time but only within their own LAN. Ranges include those IPs that start with 10, 172 or 192
How can you route private IPs through a public IP?
By using network address translation (NAT).
What is a loopback address? Give the IP.
An address that creates a loopback to the host and is often used in troubleshooting and testing network protocols on a system. 127.0.0.1
When would automatic private IP addresses (APIPA) be used?
Give the IP range.
When a device does not have a static IP address or cannot reach a DHCP server.
169.254.0.0 to 169.254.255.255
What is the acronym for the process of obtaining an address from a DHCP server?
DORA: Discover, offer, request, acknowledge
How do you statically assign an IP address?
Manually type the IP address for the host, its subnet mask, default gateway and DNS server (impractical on large enterprise networks)
What does DNS do?
Converts the domain names used by a website to the IP address of its server (the internet version of a phonebook)
What does Windows Internet Name Service (WINS) do?
Identifies NetBIOS systems on a TCP/IP network and converts those names to IP addresses
What does Bootstrap Protocol (BOOTP) do?
Dynamically assigns IP addresses and allows a workstation to load a copy of a boot image to the network
What does DHCP do?
Give the IP range.
Assigns an IP based on an assignable scope of addresses and provides the ability to configure other options. Each IP is leased and returned to the pool when lease expires
192.168.1.100 to 192.168.1.200
What is the modern implementation of BOOTP?
DHCP
Name a positive and negative of APIPA.
- Allows for quick configuration of a LAN without the need for a DHCP server
- APIPA-assigned devices cannot communicate outside the LAN or with non-APIPA devices
What does ZeroConf do?
(Name three things.)
- Assigns IPv4 link-local addresses to a client
- Resolves computer names to IP addresses using mDNS
- Performs service discovery on a network (essentially the same features as APIPA)
What is ZeroConf called on Windows and Linux?
Windows: Link-local Multicast Name Resolution (LLMNR)
Linux: SystemD
What is scope (in context of DHCP)?
The list of valid IP addresses available for assignment or lease to a client computer or endpoint device on a given subnet. There are 254.
What does DHCP do?
Provides an IP address to every machine on the network and eliminates configuration errors
What is DHCP reservation?
Excluding some IP addresses from being handed to devices unless they meet a certain condition
How does DNS help network clients find a website?
By using human-readable hostnames instead of numeric IP addresses
Define a fully-qualified domain name (FQDN).
A domain name under a top-level provider
What does the Uniform Resource Locator (URL) contain?
The FQDN with the method of accessing information
What can CNAME records be used for?
To point to another domain or subdomain (not to an IP address)
What DNS record has the function of linking a hostname to an IPv6 address?
AAAA
Define Sender Policy Framework (SPF).
A DNS record that identifies the host authorised to send mail for the domain
What does DKIM do?
Provides the cryptographic authentication mechanism for mail using a public key published as a DNS record
What is DMARC?
A framework that is used for proper application of SPF and DKIM, utilising a policy that is published as a DNS record
What is a nameserver?
A type of DNS server that stores all the DNS records for a given domain
What does internal DNS do?
Allows cloud instances on the same network to access each other using internal DNS names
What is external DNS?
Records created around the domain names from a central authority and used on the public Internet