Network Configuration Flashcards
Link/Network Interface Layer
Responsible for putting frames in the physical network’s transmission data. (ex. copper twisted pair cable, fiber optic cable). Data can only travel through the local area network.
Internet Layer
Used to address packets and route them across the network.
Transport Layer
Shows How to send the packets.
-Transmission Control Protocol (TCP): Guaranteed connection oriented method of ending packets from one deice to another, slower than UDP
0User Datagram Protocol (UDP): Connectionless protocol, faster than TCP but delivery is not guaranteed
Application Layer
Contains all the protocols that perform higher-level functions (e-mail, file transfer, encryptions, ect.)
IPv4 addresses can be broke into classes
See table!
Multicast Address
A logical identifier for a group of hosts in a computer network (ex, a group chat in Facebook, multicast works the same way)
Class A Network
1st octate: 1-127
Default Subnet Mask: 255.0.0.0
Possible hosts: 256 x 256 x 256 = 16.7 million
Class B Network
1st octate: 128-191
Default Subnet Mask: 255.255.0.0
Possible hosts: 256 x 256 = 65,536
Class C Network
1st octate: 192-223
Default Subnet Mask: 255.255.255.0
Possible hosts: 256
Class D Network
1st octate: 224-239
Does not have subnetmask assigned to it
Works as a Multicast Address
Class E Network
1st octate: 240-255
Reserved for experimental purposes
Possible hosts: 268 million
Classful Mask
Default subnet mask for a given class of IP addresses
Classless Inter-Domain Routing (CIDR)
Allows for borrowing some of the host bits and reassigning them to the network portion
Ex.
Class C subnet
255.255.255.0
This can be changed to…
255.255.255.192
This essentially divides our host into 4 smaller networks with 64 hosts each. This is known as a CIDR notation
example!
192.168.1.4
255.255.255.0
abbreviates to…
192.168.1.4/24
192.168.1.4
255.255.255.192
abbreviates to…
192.168.1.4/26
Class A CIDR notation
/8
Class B CIDR notation
/16
Class C CIDR notation
/24
IPv4 Public (routable)
Can be accessed ove the Internet and is assigned to the network by an Internet Service Provider
IPv4 Private (non-routable)
Can be used by anyone any time, but only within their own local network. Private Ip ranges include those that start with either 10, 172, or 192
Network Address Translation (NAT)
Allows for routing of private IPs through a public IP
Ranges for private IP addresses (IMPORTANT TO MEMORIZE!!!!)
Class A
-Starting value: 10
-IP Range: 10.0.0.0-10.255.255.255
-Possible hosts: 16.7 million
Class B
-Starting value: 172.16 - 172.31
-IP Range 172.16.0.0 - 172.31.255.255
-Possible Hosts: 1.05 million
Class C
-Starting Value: 192.168
-IP Range 192.168.0.0 - 192.168.255.255
-Possible Hosts: 65,536
Loopback Address (127.0.0.1)
Creates a loopback to the host and is often used in troubleshooting and testing network protocols on a system
Automatic Private IP Addresses (APIPA)
Used when a device does not have a static IP address or cannot reach a DHCP server. Range is from 169.254.0.0 to 169.254.255.255
D.O.R.A.
Discover
Offer
Request
Acknowledge
IPv4 Static Assignment
Manually type the IP address for the host, its subnet mask, fault gateway, and DNS server
Dynamic Assignment
Dynamic allocation of IP addresses
Domain Name System (DNS)
Converts the domain names used by a website to the IP address of its server. Essentially the internet version of a phone book.
Windows Internet Name Service (WINS)
Identifies NetBIOS systems on a CTP/IP network and converts those NetBIOS names to IP addresses
Bootstrap Protocol (BOOTP)
Dynamically assigns IP addresses and allows a workstation to load a copy of boot image to the network
Dynamic Host Control Protocol (DHCP)
Assigns an IP based on an assignable scope or addresses and provides the ability to configure other options. You can configure scope. DHCP is the modern implementation of BOOTP
Example:
Only assign addresses 192.168.1.100 through 192.168.1.200
Each IP is leased for a period of time and returns to the pool when the lease expires.
DHCP provides:
-IP address
-Subnet Mask
-Default Gateway
-DNS/WINS server
Automatic Private IP Addressing (APIPA)
Used when a device does not have a static IP address or cannot reach a DHCP server. Allows for the 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
Zero Configuration (ZeroConf)
New technology the provides the same features as APIPA. Can Resolve computer name to IP addresses without the need for DNS by using the mDNS(multicast domain name server). It can perform service discovery on a network.
Dynamic Host Configuration protocol (DHCP)
Provides an IP address to very machine on the network and eliminates configuration errors.
Scope
List of valid IP addresses available for assignment or lease to a client computer or endpoint device on a given subnet
DHCP Reservation
Excludes some IP addresses from being handed to devices unless they meet a certain condition. (Ex. set a DHCP reservation for a printer based on its mac address. Default lease time in home networks is 24 hours. For corporate, 7 to 30 days.
4 steps of configuring a network using DHCP?
Discover
Offer
Request
Acknowledge
Domain Name System (DNS)
Helps network clients find a website using human-readable hostnames instead of numeric IP addresses
Fully-Qualified Domain Name (FQDN). (Check table in presentation 100 at 6:27 for domain hierarchy)
Domain name under a top-level provider (ex. .com, .org)
example:
service.domain name.top-level domain
(www.diontraining.com)
Uniform Resource Locator (URL)
Contains the FQDN with the method of accessing information
ex.
https://
http://
ftp://
DNS records within a DNS Server
A
-Description: Address
-Function: Links a hostname to an IPv4 Address
AAAA
-Description: Address
-Function: Links a hostname to an IPv6 Address
CNAME
-Description: Canonical Name
-Function: Points a domain to another domain or subdomain (ex. www.itil4exam.com redirects to www.diontraining.com). Can only be used to point to another domain or subdomain, not to an IP address
MX
-Description: Mail Exchange
-Function: Directs emails to a mail server
TXT
-Description: Text
-Function: Adds text into the DNS (Can add SPF, DKIM, DMARC information)
-Sender Policy Framework (SPF): DNS record that identifies the host authorized to send mail for the domain
-DomainKeys Identified Mail (DKIM): Provides the cryptographic authentication mechanism for mail using a public key published as a DNS record
-Domain-based Message Authentication, Reporting & Conformance (DMARC): Framework that is used for proper application of SPF and DKIM, utilizing a policy that’s published as a DNS record
NS
-Description: Nameserver
-Function: Indicates which DNS nameserver has the authority
Nameserver
Type of DNS server that stores all the DNC records for a given domain
Internal DNS
Allows cloud instances on the same network access each other using internal DNS names
External DNS
Records created around the domain names from a central authority and used on the public internet
Time to Live (TTL)
Tells the DNS resolver how long to cache a query before requesting a new one
DNS Resolver/DNS Cache
makes a local copy of every DNS entry it resolves when connecting to websites
Recursive Lookup
DNS server communicates with several other DNS servers to hunt down the IP address and return to the client.
Iterative lookup
Each DNS server responds directly to the client with an address for another DNS server that may have the correct IP address
What do you need to know about DNS for the exam?
-How DNS works (DNS records)
