Chapter 16 - 01 - Discuss Network Troubleshooting - 06_ocred_fax_ocred.pdf

Certified Cybersecurity Technician Exam 212-82 Network Troubleshooting Troubleshooting Network Issues: Physical Connect...

Certified Cybersecurity Technician Exam 212-82 Network Troubleshooting Troubleshooting Network Issues: Physical Connectivity Issues Steps to Troubleshoot Physical Connectivity Issues QO Check for cable connectivity issues: » Check that suitable cables are used for connections between devices » Loose connections are to be avoided » If there are no loose connections, check for old cables and replace them with new ones and then try to connect the device » If the problem persists, then it may be faulty port issue QO Q Check for faulty ports: » Check the ports where the link is established and confirm that the indicator lights are on Q check cCheck for traffic overload: » Crosscheck the capacity of the devices in the network and the traffic flowing through it 51 » Exceeding the specified limit could lead to the interruption of communication between A_eiging the source and destination Troubleshooting Network Issues: Physical Connectivity Issues Steps to Troubleshoot Physical Connectivity Issues = Check for cable connectivity issues: The user should primarily check that the network cable is plugged in. If the cable is not plugged in, then plug it into the network card of the computer. If the cable is securely plugged in, then reboot the system and check for cable connectivity issues. The cable used to connect computers may be physically damaged, shorted, or faulty. Check that suggested and suitable cables are used for connections between devices. For example, check that the connectivity between a router and computer is established using a crossover pair of cables. Loose connections are to be avoided. If there are no loose connections, check for old cables and replace them with new ones and attempt to connect the device. If the problem persists, then it can be a faulty port issue. = Check for faulty ports: Check the ports where the link is established and confirm that the indicator lights are on. The user should verify the duplex mode and speed. If the port is working properly but the connectivity issue persists, then check the indicator lights on each device to determine the working status of the port. Check whether the port is physically radiating or the indicator lights are off. From the light status, the user can determine whether the port is physically malfunctioning. In this scenario, the user should configure the link on some other free port/interface. = Check for traffic overload: Crosscheck the capacity of the devices in the network and the traffic flowing through it. Exceeding the specified limit could lead to the interruption of communication between the source and destination. If traffic overload occurs at the link or interface, then it would function abnormally at some point; therefore, the user should verify these criteria to avoid any connectivity issues. Module 16 Page 1960 EG-Council Certified Cybersecurity Technician Copyright © by EG-Bouncil All Rights Reserved. Reproduction is Strictly Prohibited. Certified Cybersecurity Technician Exam 212-82 Network Troubleshooting Troubleshooting Network Issues: Local Connectivity Issues Steps to Troubleshoot Local Connectivity Issues ¢ Ping the destination if the source and the destination are of the same subnet mask ¢ Ping the gateway IP of the router if the source and destination are not of the same subnet mask +¢ If the ping fails, check that the route followed by the subnet mask is defined correctly in the routing table ¢« If everything is fine, check if the source is pinging a hop/router in the network ¢% If the ping fails, it could be a configuration issue or an IP address conflict ¢ Resolve any IP address conflict by disconnecting the doubtful device and pinging it with other devices in the network ¢«¢ If the device is pinging, then the disconnected device was using the same IP as the pinged device. Then, modify the IP according to the plan Copyright © by All Rights Reserved. Reproduction s Strictly Prohibited. Troubleshooting Network Issues: Local Connectivity Issues If the user encounters LAN connectivity issues, then to identify the root cause and resolve the issue, it is recommended to follow the steps below. Steps to Troubleshoot Local Connectivity Issues = The user should ping the destination IP if the source and destination are of the same subnet mask. = The user should ping the gateway IP of the router if the source and destination are not of the same subnet mask. = |n case both pings fail, then the user must check whether the configuration settings of the subnet mask and the route to the destination are defined properly in the routing table. = |If the configuration settings are fine, then the user should check whether the source host can ping a different hop in the LAN network other than the destination host. = |If the user is unable to ping another device, then there might be various issues such as IP address conflict, configuration issues, and physical connectivity issues. *= To rectify any IP address conflict, the user should disconnect all doubtful devices from the LAN. At this point, the user needs to ping the device from some other device on the same subnet/LAN. A successful ping signifies that the disconnected device is using the same IP as the pinged device; then, modify the IP according to the plan. If the local connectivity issue persists, then there might be a problem with the physical connectivity or configuration. Module 16 Page 1961 Certified Cybersecurity Technician Copyright © by EG-Council All Rights Reserved. Reproduction is Strictly Prohibited. Certified Cybersecurity Certified Cybersecurity Technician Technician Exam 212-82 Exam 212-82 Network Troubleshooting Troubleshooting Network Issues: Routing Problems ===Y ) Steps to Troubleshoot Physical Routing Issues 2 7 Use the traceroute utility to locate the hop/router responsible for the problem O = — === =) S PO00000 If the issue persists, investigate each hop/router to find where the S problem has occurred = When the problematic hop/router is detected, login to it using S Telnet and ping the destination and source g g S = =g = If the ping is unsuccessful, configure the routes between the source and destination with a subnet mask if they are not defined - Check for a routing loop by pinging again. If it exists, rectify it by tracing - - and reconfiguring the routing - Check the routing protocol if the problem persists, and change it according to the network O = Troubleshooting Network Issues: Routing Problems When data packets are routed across a network, there are chances of fault occurrence. Based on the type of fault, the user should make a plan to resolve the fault. The type of faults that are observed between source and destination hosts when data packets are routed across a network are as follows: Failure to define the route in a router between the source and destination Usage of an incorrect routing protocol to find the route to the next hop/destination Fault in the router’s software Firewall or filter hindering the movement of data packets to the destination node Configuration faults at the source router end Steps to Troubleshoot Routing Issues The first step to troubleshoot routing issues is to locate the hop between the source and destination where the problem occurred. From the source to the destination, verify the IP connectivity and routing protocols at each hop. Use the traceroute utility to locate the hop/router responsible for the problem. After identifying the hop where the problem occurred, login to the router through Telnet and ping the source and destination hosts. If the is unsuccessful, then the routing table should ping be verified for the route between the source and destination. Module 16 Page 1962 Certified Cybersecurity Technician Copyright © by EC-Gouncil EG-Council All Rights Reserved. Reproduction is Strictly Prohibited. Certified Cybersecurity Technician Exam 212-82 Network Troubleshooting = |f there is a small percentage of successful ping responses, then there might be multiple defined paths to reach the destination, among which one results in failure owing to the occurrence of a routing loop in the path. To resolve this issue, the looping hop should be traced, and the configuration should be rectified. = After rectification, if the problem persists, then check the used routing protocol and change it according to the network. Module 16 Page 1963 Certified Cybersecurity Technician Copyright © by EG-Council All Rights Reserved. Reproduction is Strictly Prohibited.