Chapter 16 - 01 - Discuss Network Troubleshooting - 01_ocred_fax_ocred.pdf

Certified Cybersecurity Technician Exam 212-82 Network Troubleshooting Module Flow...

Certified Cybersecurity Technician Exam 212-82 Network Troubleshooting Module Flow Learn Troubleshooting Basic Network Issues using Utilities and Tools Discuss Network Troubleshooting This section discusses common network issues and various troubleshooting techniques to resolve them. Module 16 Page 1926 Certified Cybersecurity Technician Copyright © by EC-Council EG-Council All Rights Reserved. Reproduction is Strictly Prohibited. Certified Cybersecurity Technician Exam 212-82 Network Troubleshooting Troubleshooting O Troubleshooting is the process of finding issues in a computer network and diagnosing them Typical Network Issues '©© 4\) Configuration Configuration Issu es Issues » Network connectivity issues due to » Network failure or faulty configuration » Misconfiguration of DHCP and DNS faulty or loose connection of cables of ports or interfaces in LAN and WAN, settings, causing routing issues that which may affect the connectivity to the result in communication failure host server Q Software Issues Q Network IP Issues » Incompatible software and version » Network behavior changes when traffic » Improper IP settings, subnet mask, and mismatch, leading to disruptions of the exceeds the capacity of the network routing at the source, resulting in the transmission of IP data packets between devices interruption of communication with the the source and destination destination IP Troubleshooting Troubleshooting is the process executed by network engineers/administrators to find issues in a computer network and diagnose them to enhance the network performance. It comprises systematic measures and processes to identify, diagnose, and resolve network issues to recover normal network operations on end nodes. Troubleshooting is primarily performed by network engineers/administrators. The process of troubleshooting can be performed manually or by using automated tools (network diagnostic software). Some of the processes involved in network troubleshooting are as follows: * Finding and resolving the faulty network connection of a system = Configuring network devices (routers, switches, etc.) = |nstalling physical equipment (cables, Wi-Fi devices, etc.) = Updating firmware devices =* Removing viruses using antivirus software =* Adding, configuring, and reinstalling devices Typical Network Issues The issues that generally occur in a network are as follows: = Physical connection issues: These issues occur due to faulty, shortened, or damaged cables in a network. For example, cut cables, incorrect cable connections, and connector problems may result in poor network connectivity. Module 16 Page 1927 Certified Cybersecurity Technician Copyright © by EG-Council All Rights Reserved. Reproduction is Strictly Prohibited. Certified Cybersecurity Technician Exam 212-82 Network Troubleshooting * Connectivity issues: These issues are caused by faulty/physical shutting down of the port or interface on which devices are connected in a LAN or WAN. For example, the malfunction of a hub, router, or switch may affect the network connectivity with the host server. = Configuration issues: These issues occur due to the faulty configuration of DHCP and DNS settings, routing issues, IP looping, etc. and may result in communication failure. = Software issues: These issues are caused by software compatibility issues and mismatched software versions. These may result in the interruption of the transmission of IP data packets between the source and destination. = Traffic overload issues: These issues occur due to traffic that exceeds the normal capacity of a network device. For example, transfers of an excessive amount of information due to a poor network setup may result in abnormal network behavior or slow connectivity. * Network IP issues: These issues are caused by the faulty configuration of IP addresses, subnet masks, and routing at the source and may result in interruption in reaching the destination IP through the network. Module 16 Page 1928 Certified Cybersecurity Technician Copyright © by EG-Council All Rights Reserved. Reproduction is Strictly Prohibited. Certified Cybersecurity Technician Exam 212-82 Network Troubleshooting Basic Network Issues: Unreachable Networks Echo Request/Reply When host is up QO An ICMP destination unreachable message is sent in the case of the following: B BN C:AWINDOWS\system32iemd.exe C:AWINDOWS\system32\emd.exe Microsoft Windows [Version 10.0.18362.778] v’v The host or port is unreachable (c) 2019 Microsoft Corporation. All rights reserved. v’v The network is unreachable C:\Users\Martinyping C:\Users\Martindping 10.10.10.16 10.10. Pinging 10.10.10.16 / with 32 bytes of data: Reply ply from 10.10.10,16: 10.10.10. 25 TTL=128 Reply from 10,10,10,16: ),10,16: m TTL-128 I do not know 'plyy from from 10.10.10,16:.10, by 2 tim TTL=128 how togetto Z| Reply Reply from 10.10.10. 10.10.10.16: by 32 t TL=128 D Send ICMP Ping statistics for.10.10.16: 4, Received = 4, Lost = Approximate round trip timeses in mill Minimum « Oms, Maximum « 1ms, Av C:\Users\Martin>g fenined Toz cvsrennnnend § Echo = Type 8; Echo Reply = Type 0 Copyright © by EC-Councll. EC-Councll. AllAll Rights Reserved. Reproduction ReproductionIss Strictly Prohibited Prohibited. Basic Network Issues: Unreachable Networks Network communication depends on certain basic conditions being met. » Sending and receiving devices must have the TCP/IP protocol stack properly configured: o The IP address and subnet mask must be properly configured. o A default gateway must also be configured if datagrams are to travel outside of the local network. = A router must also have the TCP/IP protocol stack properly configured on its interfaces, Arouter and it must use an appropriate routing protocol. = |f these conditions are not met, then network communication cannot occur. = The following are examples of problems: o The sending device may address the datagram to a non-existent IP address. o The destination device is not connected to its network. o The router’s connecting interface is down. o The router does not have the information necessary to find the destination network. = An ICMP destination unreachable message is sent in the case of the following issues: o Host or port unreachable o Network unreachable Module 16 Page 1929 Certified Cybersecurity Technician Copyright © by EG-Council All Rights Reserved. Reproduction is Strictly Prohibited. Certified Cybersecurity Technician Exam 212-82 Network Troubleshooting Sond data | do not know to Z how tc:iget to Z! Data Send ICMP Network A. || S QD e : | |A : A E :--o-----) Toz assssssssens g Ceanann Destination Unreachable ping 10.10.10.16 Pinging 10.10.160. 10.10.10. 16 with 32 bytes of data: Reply from 10.10. 10. 16 : bytes=32 time=1ms TTL=128 Reply from 10.10. 10. [} bytes=32 116: time