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✓ 4.1 Given a scenario, implement the following network troubleshooting methodology:

■ Identify the problem

■ Gather information

■ Duplicate the problem

■ Question Users

■ Identify symptoms

■ Determine if anything has changed

■ Approach multiple problems individually

■ Establish theory of probable cause

■ Question the obvious

■ 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

■ Interface errors

■ Split horizon

■ DNS issues

■ Interference

■ Router configurations

■ Customer premise equipment

■ Smart jack/NIU

■ Demarc

■ Loopback

■ CSU/DSU

■ Copper line drivers/repeaters

■ Common security policy

■ Throttling

■ Blocking

■ Fair access policy/utilization limits

■ Satellite issues

■ Latency