Network+ Review

AAAA

Designed to map a domain name to an IPv6 Address

A

Maps a domain name to an IPv4 Address

CNAME

alias one domain name to another, not to an IP

TXT

Provides human-readable information about a domain

MX

Allows Outgoing (SMTP) and Incoming (POP3/IMAP) traffic

PTR

Used for reverse DNS lookup

RST Flag

Reset flag, used to terminate connection

FIN Flag

Finish Flag, used to request that the connection be terminated

SYN Flag

Set in the first packet sent as a means of establishing a TCP connection and initializing a three-way handshake.

ACK Flag

Sent as a reply from SYN packet to complete three way handshake and begin data transmission

Cable Certifier

Used to test the continuity of a cable and verify that it meets bandwidth frequency and length requirements

Cable Crimper

Used to join the internal wires of a twisted pair cable with metallic pins inside a plastic connector

Punchdown Tool

Used to insert wires into insulation displacement connectors on patch panels.

Security Service Edge (SSE)

Integrates threat intelligence capabilities to detect and respond to securiy incidents in real-time.

Spanning Tree Protocol

• Builds a logical loop-free topology for Ethernet Networks.

• Main function is to prevent bridge loops and the broadcast radiation that results from them.

Link Layer Discovery Protocol (LLDP)

Same purpose as CDP (network discovery), but is an open standard for multiple vendors.

Cisco Discovery Protocol (CDP)

Main purpose is Network Discovery for Cisco Devices.

Microwave Connections

Ideal for Mountainous regions, offering high-speed data transmission over short distances.

Sattellite connections

Wireless communication links that use orbiting satellites to transmit data between locations, such as for internet, TV, and phone services.

High-frequency Radio

Radio frequencies from 3 MHz to 30 MHz used for long‑distance communication.

Access Control List (ACL's)

Used to filter network traffic based on specified criteria. (source and destination IP, ports, protocols, etc.)

802.11a Frequency/Speed

5 GHz, 54 Mbps

802.11a

• Data rates up to 54 Mbps.

• Faster than 802.11b

• Shorter Range

802.11b Frequency/Speed

2.4 GHz, 11Mbps

802.11b

Longer Range but lots of interference

802.11g Frequency/Speed

2.4 GHz, 54Mbps

802.11g

Combines b's range with a's speed.

802.11n Frequency/Speed

• 2.4 & 5 GHz

• Wi-Fi 4

• 600 Mbps

802.11n

Enhances wireless network speed and range; supports multiple input and output (MIMO) technology.

802.11ac Frequency/Speed

• 5 GHz

• Wi-Fi 5

• 6.9 Gbps

802.11ax Frequency/Speed

• 2.4 & 5 GHz /6 GHz

• Wi-Fi 7

• 9.6 Gbps

802.11 ax

OFDMA, better efficiency in crowded networks

802.11be

Multi-Link Operation (MLO), 320MHz channels, extremely high throughput

Wi-Fi 7

46 Gbps

ARP Spoofing

Threat actor sends falsified ARP messages over a LAN. Results in the linking of an attackers MAC with the IP of a computer or server on the network.

MAC Spoofing

The act of changing a device’s MAC address to impersonate another device or hide its identity.

DNS Poisoning

A technique that corrupts DNS cache entries to redirect users to malicious IP addresses.

Evil Twin

A rogue Wi‑Fi access point that masquerades as a legitimate one to lure users and intercept traffic

IP Spoofing

A technique that falsifies the source IP address in packet headers to appear as a different host.

Phishing

A fraudulent attempt to obtain personal or confidential information by posing as a legitimate or trusted entity.

DoS

A denial‑of‑service attack that aims to make a network service unavailable to its users.

DDoS

A distributed denial‑of‑service attack that overwhelms a target’s network or services with traffic from multiple compromised sources.

WEP

Wired Equivalent Privacy, an early Wi‑Fi security protocol using 64‑ or 128‑bit RC4 encryption, now considered insecure.

WPA‑Personal (PSK)

Pre‑shared key authentication using a shared passphrase for WPA‑Personal.

WPA‑Enterprise (EAP)

A Wi‑Fi security mode that uses 802.1X/EAP for authentication, providing per‑user credentials and dynamic encryption keys.

WPA2‑Personal (PSK)

Pre‑shared key authentication for home/small‑office Wi‑Fi, using AES encryption.

WPA2‑Enterprise (EAP)

A Wi‑Fi security mode that uses WPA2 with 802.1X authentication, requiring each user to authenticate through an external RADIUS server via an Extensible Authentication Protocol (EAP) method.

WPA3‑Personal

A Wi‑Fi security protocol that uses SAE (Simultaneous Authentication of Equals) for stronger password‑based authentication and provides enhanced encryption compared to WPA2‑Personal.

WPA3‑Enterprise

An enterprise‑grade Wi‑Fi security protocol that uses 802.1X authentication with SAE‑based WPA3 encryption for stronger protection in corporate networks.

Simultaneous Authentication of Equals (SAE)

A mutual authentication process in which both parties verify each other simultaneously, typically used in peer‑to‑peer authentication protocols.

AES Encryption

A symmetric block cipher that uses 128‑bit blocks and key sizes of 128, 192, or 256 bits to securely encrypt data.

RIP (Routing Information Protocol)

Determines the best route based on Hop Count

• Maximum 15 hops

OSPF: Open Shortest Path First

Link-State Routing Protocol

• Uses Cost instead of Hops (Cost is based on bandwidth)

EIGRP: Enhanced Interior Gateway Routing Protocol

Find the best route and a backup route (DUAL Algorithm)

• Considers multiple factors (bandwidth, delay)

• Developed by CISCO

BGP: Border Gateway Protocol

Used to route traffic between different autonomous systems

• Basically the routing protocol of the internet

Autonomous Systems

Network or collection of networks under a common administrative organization

Static NAT

A permanent one-to-one mapping of a private IP to a public IP.

Dynamic NAT

Private IPs map to a pool of public IPs on a first-come basis.

PAT (NAT overload)

Many private IPs share one public IP. The router keeps them apart by assigning unique source port numbers.

Native VLAN

The VLAN whose traffic crosses an 802.1Q trunk untagged.

Subnet mask sequence /25 to /30

25=128, /26=192, /27=224, /28=240, /29=248, /30=252 (last octet).

Each extra network bit adds the next bit value: 128, 64, 32, 16, 8, 4.

802.1X

Port based network access control

Forces a device to authenticate before it's allowed onto the network.

RADIUS

Open-standard AAA protocol for end-user network access (Wi-Fi, VPN, 802.1X).

TACACS+

Cisco-developed AAA protocol for administering network devices.

Kerberos

Ticket-based SSO used by Active Directory.

Unicast

One sender to one receiver.

Broadcast

One sender to ALL hosts on the local subnet.

Multicast

One sender to a group of subscribed receivers, e.g., video streaming or routing protocol updates.

Anycast

One address shared by multiple servers; traffic goes to the nearest one. Used by DNS root servers and CDNs.