Network Services

CompTIA+ Network Learning

Dynamic Host Configuration Protocol (DHCP)

Dynamic Host Configuration Protocol (DHCP)

A network management protocol used for automatic assignment of IP addresses, subnet mask, default gateway, and DNS server to devices connecting to the internet.

Domain Name System (DNS)

A protocol used to convert domain names to IP addresses, acting as a phone book for the internet. It operates over UDP and TCP using port 53.

Network Time Protocol (NTP)

A networking protocol used for clock synchronization between computer systems over a packet-switched network. It uses UDP over port 123.

DHCP Lease

The period of time for which a device is assigned an IP address by the DHCP server. Default lease time is usually 24 hours, but can be longer in corporate networks.

DORA

A mnemonic for the four steps of configuring a device using DHCP - Discover, Offer, Request, and Acknowledge.

DHCP Reservation

A method of excluding specific IP addresses from being handed out by the DHCP server, allowing them to be reserved for specific devices based on conditions such as MAC address.

Static Assignment

Manually providing an IP address, subnet mask, default gateway, and DNS server to a device instead of using DHCP for configuration.

Alternate Configuration

A fallback configuration set by the system administrator in case DHCP fails or cannot provide a proper configuration to a device.

APIPA

Automatic Private IP Address, a default setting that assigns a private IP address to a device if no other IP address is available.

Static IP address

A manually configured IP address that does not change.

DHCP server

A server that assigns IP addresses and other network configuration settings to devices on a network.

Scope options

Configuration settings in a DHCP server that include subnet mask, default router/gateway, DNS server, and lease time.

DHCP relay

A host that forwards DHCP packets between clients and servers when they are not on the same subnet.

User Datagram Protocol (UDP)

The protocol used by DHCP to send data, operating as a fire and forget method.

IP helper address

An address configured on a router to forward UDP broadcasts, often used in conjunction with DHCP relay.

DORA process

The process of DHCP discovery, offer, request, and acknowledgement that assigns an IP address to a device.

DHCP reservation

A configuration that assigns a specific IP address to a device using DHCP, ensuring it always receives the same address.

DHCP server settings

Configuration settings in a DHCP server, including start IP address, maximum number of users, and DHCP reservations.

DHCP

Dynamic Host Configuration Protocol. It is a network protocol that enables automatic assignment of IP addresses and other network configuration parameters to devices on a network.

DORA process

It stands for Discover, Offer, Request, and Acknowledge. It is the sequence of steps that takes place between a client and a DHCP server to obtain an IP address and other configuration information.

Scopes

Scopes in DHCP refer to a range of IP addresses that can be assigned to clients. It defines the available IP addresses and other configuration settings that can be offered by the DHCP server.

Reservations

Reservations in DHCP allow specific IP addresses to be assigned to specific clients based on their MAC address. It ensures that a particular device always receives the same IP address from the DHCP server.

DNS

Domain Name System. It is a protocol that translates human-readable domain names into numeric IP addresses, allowing network clients to find websites using host names instead of IP addresses.

Fully Qualified Domain Name (FQDN)

It is a domain name that includes the top-level domain, second-level domain, subdomain, and host name. It provides a complete and unique address for a specific resource on the internet.

A record

Address record. It links a host name to an IPv4 address in the DNS server. It allows clients to resolve a domain name to its corresponding IP address.

AAAA record

It stands for IPv6 Address record. It maps a domain name to an IPv6 address in the DNS server. It is used for websites that support IPv6 addresses.

CNAME record

Canonical Name record. It is used to point a domain or subdomain to another domain or subdomain name. It provides an alias or nickname for a specific domain name.

CNAME record

A DNS record that points a domain or subdomain to another domain or subdomain.

MX record

A DNS record that specifies the mail server responsible for accepting incoming emails for a domain.

SOA record

A DNS record that stores important information about a domain or zone, such as the last update time and the email address of the domain administrator.

PTR record

A DNS record used for reverse DNS lookup to correlate an IP address with a domain name.

TXT record

A DNS record used to add human-readable or machine-readable text data into the DNS system, often used for domain ownership verification or email spam prevention.

SRV record

A DNS record used to specify a host and port for a specific service, such as voiceover IP or instant messaging.

NS record

A DNS record used to indicate the authoritative DNS name server for a domain.

DNS records

Information stored for a given domain, including different types such as A record, AAAA records, Canonical Name records, MX records, TXT records, PTR records, and SRV records.

Name server

A server that stores DNS records for a domain and can be primary or backup.

Cloudflare

A cloud service provider that hosts name servers for domains.

Internal DNS

DNS used within a private network or cloud environment to allow instances to access each other using internal DNS names.

TTL (Time to Live)

A setting associated with DNS records that determines how long a DNS resolver can cache a query before requesting new information.

DNS cache

A temporary database located on individual hosts that stores DNS records to speed up the resolution process.

Recursive lookup

A DNS lookup strategy where the resolver asks DNS servers in a hierarchical manner until it finds the authoritative source for the domain.

Iterative lookup

A DNS lookup strategy where the resolver asks DNS servers for information and continues to query until it finds the IP address for the domain.

A records

DNS records used to map domain names to IPv4 addresses.

AAAA records

DNS records used to map domain names to IPv6 addresses.

CNAME records

DNS records used to map domain names to other domain names.

MX records

DNS records used for email and specify mail exchange servers for a domain.

NS records

DNS records used to specify name servers for a domain.

TXT records

DNS records used to store text data, either human-readable or machine-readable.

Pointer records

DNS records used to match an IP address with a domain name for reverse DNS lookups.

Service records

DNS records used to map a port and IP address to a domain name for a service.

DNS Server

A server that translates domain names into IP addresses.

ARP Packet

A packet used to discover the MAC address of a device on a local network.

Broadcast

Sending a message to all devices on a network.

MAC Address

A unique identifier assigned to network interfaces.

Switch

A network device that connects devices on a local network.

Client

A device that requests services or resources from a server.

DNS Records

Information stored on a DNS server that maps domain names to IP addresses.

Gateway

A device that connects different networks and forwards traffic between them.

ISP Router

A router provided by an Internet Service Provider (ISP) to connect to the internet.

Layer 2

The data link layer in the OSI model responsible for transferring data between adjacent network nodes.

Layer 3

The network layer in the OSI model responsible for routing and forwarding data packets.

IP Address

A numerical label assigned to each device connected to a computer network.

Router

A network device that forwards data packets between computer networks.

DNS Packet

A packet containing a DNS query or response.

Name Server

A server that handles queries regarding domain names within a specific domain.

Authority Record

A DNS record that specifies the authoritative name server for a domain.

Start of Authority (SOA) Record

A DNS record that contains administrative information about a domain.

A Record

A DNS record that maps a domain name to an IPv4 address.

Subdomain

A domain that is part of a larger domain.

Layer 3 Addressing

The process of assigning IP addresses to devices for communication over a network.

DNS server

A server that translates domain names into IP addresses and vice versa.

ARP packet

A packet used in the Address Resolution Protocol (ARP) to map an IP address to a MAC address.

Authority.diontraining.com

The domain name of the server that is the authority for the diontraining.com domain.

DNS request

A request sent by a client to a DNS server to obtain the IP address associated with a domain name.

Cache

A temporary storage location where DNS servers store recently accessed DNS records for faster retrieval.

Root DNS server

The highest level of DNS servers in the DNS hierarchy responsible for directing DNS queries to the appropriate authoritative name servers.

A record

A type of DNS record that maps a domain name to an IP address.

C name record

A type of DNS record that maps a domain name to another domain name.

Time to live (TTL)

The amount of time a DNS record can be cached before it expires and needs to be refreshed.

IP address

A unique numerical label assigned to each device connected to a computer network.

MAC address

A unique identifier assigned to network interfaces for communication at the data link layer of a network segment.

HTTP traffic

Internet traffic using the Hypertext Transfer Protocol (HTTP) for communication between clients and servers.

HTTP

A protocol used to send and receive webpages over the internet.

Packet

A unit of data that is transmitted over a network.

Mac address

A unique identifier assigned to a network interface controller for communications at the data link layer of a network segment.

Default gateway

A network node that serves as an access point to another network.

Router

A networking device that forwards data packets between computer networks.

IP address

A numerical label assigned to each device participating in a computer network that uses the Internet Protocol for communication.

DNS server

A server that translates domain names into IP addresses.

ARP

Address Resolution Protocol, a protocol used to map an IP address to a physical or MAC address.

Switch

A networking device that connects devices on a computer network by using packet switching to receive, process, and forward data to the destination device.

Server

A computer or system that manages network resources and provides services to clients.

NTP

Network Time Protocol, a protocol used for the synchronization of clocks between computer systems over a network.

UDP

User Datagram Protocol, a transport layer protocol used for communication over IP networks.

Stratum

A level or layer in the hierarchy of NTP time sources.

Stratum 0

The most precise timekeeping devices, such as atomic clocks and GPS, that serve as reference clocks for NTP.

Stratum 1

NTP servers that are synchronized to within a few microseconds of a Stratum 0 device.

Stratum 2

NTP servers that are connected to synchronized Stratum 1 servers.

Stratum 3

NTP servers that are synchronized upward to Stratum 2 servers.

Domain controller

A server that authenticates users, stores security policies, and manages the distribution of software and updates within a Windows domain.