Network+ Domain 5: Network Troubleshooting

netstat

TCP/IP utility for network monitoring and troubleshooting

arp

Tool to view MAC addresses associated with IP addresses

dns resolution

Process of converting hostnames to IP addresses

troubleshooting strategy

Sequence to identify and resolve network issues

multicast flooding

Network issue causing performance degradation

broadcast storms

Network issue with excessive broadcast traffic

CRC errors

Cyclic Redundancy Check errors indicating data corruption

wireless access points

Devices for wireless network connectivity

network access control

Solution to manage device access on a network

misconfigured wireless router

Improper settings causing network connectivity issues

routing issue

Problem with directing network traffic

Gigabit Ethernet

High-speed network technology

multimeter

Tool for measuring voltage, amps, and ohms

VLAN isolation

Network segmentation to isolate devices

intranet site issue

Problem accessing internal network resources

console port cable

Cable used to connect to a router for configuration

wireless hotspot issue

Problem with wireless internet access

network collisions

Conflicts in data transmission on a network

TDR tests

Cable fault identification and testing

Class of Service (CoS)

Priority levels for network traffic

broadcast storm mitigation

Strategies to reduce broadcast storm effects

Ping

TCP/IP utility for testing network connectivity

Failed network card

Possible issue when no link light appears on a network card

Netstat

Utility to display active network connections

DHCP scope exhaustion

Denial of service due to IP address pool depletion

VLANs

Feature to segregate network traffic for different purposes

Crossover cable

Type of cable to connect two devices directly

Router software patch

Solution for a router going offline periodically

ARP

Utility to view MAC addresses associated with IP addresses

Plenum-rated cable

Cable type suitable for areas with air circulation

Short circuit

Condition where signals are improperly transmitted due to cable damage

Physical Contact polish

Grade of polish for fiber optic cable connectors

Denial-of-service attack

Network issue causing devices to not receive IP configurations

Straight-through cable

Cable type for connecting a workstation to a switch port

Network cabling fault

Likely cause for a client system unable to connect to a server

Auto-MDI unsupported cable

Type of cable needed for connecting a workstation to a switch without auto-MDI support

Wireless Site Surveys

Identify interference sources and access point placement.

dig

Utility producing DNS query output.

-axfr

Append to dig for all zone records query.

tracert

Check packet route between workstation and DNS server.

802.11ac

Utilizes 2.4 GHz ISM band with fast transmission rates.

ipconfig /renew

Command to force new IP configuration.

ping

Check TCP/IP connection status.

Loopback Plug

Connect RJ45 wires to create loopback.

Switching Loop

Likely cause of DHCP issue with new workstation.

ifconfig

View default gateway info on Linux server.

Wireshark

Tool for network sniffing and packet analysis.

ACME, Inc

Company name from Wireshark packet capture.

ipconfig

Utility giving specific TCP/IP output.

169.254.1.17

IP address indicating network issue.

ipconfig /flushdns

Command to clear local DNS cache.

Subnet Mask

Configuration value affecting inter-subnet communication.

netstat -n

Utility providing specific TCP/IP output.

-SXX port 443

Tcpdump option for capturing packet data.

202.64.49.150

IP address of DNS server from dig output.

Default Gateway

Parameter to check for network access issues.

FEXT

Likely issue after moving cable router.

Mounting Brackets

Essential item for site survey kit.

Overlapping Channels

Possible cause of wireless connectivity issues.

Crossover

Cable type for connecting router to switch uplink.

WPA2-PSK

Security protocol used in a wireless network.

Straight-through

Cable type for connecting different devices like a computer to a switch

Rollover

Cable type used to connect a computer's console port to a router or switch

Loopback

Cable type used to test the functionality of network ports by looping back transmitted signals

RADIUS authentication

Authentication method commonly used for wireless networks to enhance security

Antenna diversity

Technique to improve wireless signal reception by using multiple antennas

Directional access points

Access points with focused signal coverage in specific directions

ARP table

Table that maps IP addresses to MAC addresses on a local network

MAC address table

Table that stores MAC addresses associated with specific ports on a switch

Routing table

Table used by routers to determine the best path for forwarding packets

State table

Table that tracks the state of network connections for firewall and routing purposes

802.11n

Wireless networking standard providing high data rates and improved range

802.11a

Wireless networking standard operating at 5 GHz for faster data rates

802.11g

Wireless networking standard operating at 2.4 GHz with good data rates

802.11b

Wireless networking standard operating at 2.4 GHz with slower data rates

OTDR

Optical Time Domain Reflectometer used to test fiber optic cables

UPC

Ultra Physical Contact polish grade with green-colored connectors for accuracy

SPC

Super Physical Contact polish grade for improved optical performance

PC

Physical Contact polish grade for standard optical connectors

APC

Angled Physical Contact polish grade for reduced signal loss

VLAN

Virtual Local Area Network for logically segmenting a network

Legacy Operating System

Outdated OS like Windows 2000 that may pose security risks

Host-based firewall

Firewall software installed on individual devices for local protection

Troubleshooting Tasks

Sequential steps to identify, analyze, and resolve network issues effectively

RJ45

Standard connector used for Ethernet networking