CompTIA Network+ Review Guide. Ferguson Bill

Consider multiple approaches

      ■ Top-to-bottom/bottom to top of OSI Model

      ■ Divide and conquer

      ■ Test the theory to determine cause

      ■ Once theory is confirmed, determine the next steps to resolve the problem

      ■ If theory is not confirmed, re-establish new theory or escalate

      ■ Establish a plan of action to resolve the problem and identify potential effects

      ■ Implement the solution or escalate as necessary

      ■ Verify full system functionality and if applicable implement preventative measures

      ■ Document findings, actions, and outcomes

      ✓ 4.2 Given a scenario, analyze and interpret the output of troubleshooting tools

      ■ Command line tools

      ■ ipconfig

      ■ netstat

      ■ ifconfig

      ■ ping/ping6/ping-6

      ■ tracert/tracert-6/traceroute6/traceroute-6

      ■ nbtstat

      ■ nslookup

      ■ arp

      ■ mac address lookup table

      ■ pathping

      ■ Line testers

      ■ Certifiers

      ■ Multimeter

      ■ Cable tester

      ■ Light meter

      ■ Toner probe

      ■ Speed test sites

      ■ Looking glass sites

      ■ WiFi analyzer

      ■ Protocol analyzer

      ✓ 4.3 Given a scenario, troubleshoot and resolve common wireless issues

      ■ Signal loss

      ■ Interference

      ■ Overlapping channels

      ■ Mismatched channels

      ■ Signal-to-noise ratio

      ■ Device saturation

      ■ Bandwidth saturation

      ■ Untested updates

      ■ Wrong SSID

      ■ Power levels

      ■ Open networks

      ■ Rogue access point

      ■ Wrong antenna type

      ■ Incompatibilities

      ■ Wrong encryption

      ■ Bounce

      ■ MIMO

      ■ AP placement

      ■ AP Configurations

      ■ LWAPP

      ■ Thin vs. thick

      ■ Environmental factors

      ■ Concrete walls

      ■ Window film

      ■ Metal studs

      ■ Wireless standard related issues

      ■ Throughput

      ■ Frequency

      ■ Distance

      ■ Channels

      ✓ 4.4 Given a scenario, troubleshoot and resolve common copper cable issues

      ■ Shorts

      ■ Opens

      ■ Incorrect termination (mismatched standards)

      ■ Straight-through

      ■ Crossover

      ■ Crosstalk

      ■ Near end

      ■ Far end

      ■ EMI/RFI

      ■ Distance limitations

      ■ Attenuation/Db loss

      ■ Bad connector

      ■ Bad wiring

      ■ Split pairs

      ■ Tx/Rx reverse

      ■ Cable placement

      ■ Bad SFP/GBIC-cable transceiver

      ✓ 4.5 Given a scenario, troubleshoot and resolve common fiber cable issues

      ■ Attenuation/Db loss

      ■ SFP/GBIC-cable mismatch

      ■ Bad SFP/GBIC-cable or transceiver

      ■ Wavelength mismatch

      ■ Fiber type mismatch

      ■ Dirty connectors

      ■ Connector mismatch

      ■ Bend radius limitations

      ■ Distance limitations

      ✓ 4.6 Given a scenario, troubleshoot and resolve common network issues

      ■ Incorrect IP configuration/default gateway

      ■ Broadcast storms/switching loop

      ■ Duplicate IP

      ■ Speed and duplex commands

      ■ End-to-end connectivity

      ■ Incorrect VLAN assignment

      ■ Hardware failure

      ■ Misconfigured DHCP

      ■ Misconfigured DNS

      ■ Incorrect interface/interface misconfiguration

      ■ Cable placement

      ■ Interface errors

      ■ Simultaneous wired/wireless connections

      ■ Discovering neighboring devices/nodes

      ■ Power failure/power anomalies

      ■ MTU/MTU black hole

      ■ Missing IP routes

      ■ NIC teaming misconfiguration

      ■ Active-active vs. active-passive

      ■ Multicast vs. broadcast

      ✓ 4.7 Given a scenario, troubleshoot and resolve common security issues

      ■ Misconfigured firewall

      ■ Misconfigured ACLs/applications

      ■ Malware

      ■ Denial of service

      ■ Open/closed ports

      ■ ICMP related issues

      ■ Ping of death

      ■ Unreachable default gateway

      ■ Unpatched firmware/OSs

      ■ Malicious users

      ■ Trusted

      ■ Untrusted users

      ■ Packet sniffing

      ■ Authentication issues

      ■ TACACS/RADIUS misconfigurations

      ■ Default passwords/settings

      ■ Improper access/backdoor access

      ■ ARP issues

      ■ Banner grabbing/OUI

      ■ Domain/local group configurations

      ■ Jamming

      ✓ 4.8 Given a scenario, troubleshoot and resolve common WAN issues

      ■ Loss of internet connectivity

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