Section 23: Troubleshooting Network Issues Flashcards
What is a Startup Configuration?
Stored in the NVRAM and contains the commands needed to initially configure a router
What is a Running Configuration?
It’s actively being used by the router at that moment
What is a VLAN Assignment?
A practice of segmenting an IT organization’s network, separating users into respective network sections
What is a Network Performance Baseline?
Defines the normal working conditions of an enterprise network infrastructure.
What is a Collision?
Occurs when two hosts on the network transmit at the same time which causes the signals to combine on the network medium.
What is a Broadcast Storm?
Occurs when a network system is overwhelmed by continuous multicast or broadcast traffic
What is a Duplicate IP Address?
Occurs when another computer on the same network has an identical IP to another workstation or server on the same network.
What is Multicast Flooding?
No specific host is associated with the multicast MAC address in the CAM table of the switch.
What is Asymmetrical Routing?
Network packets leave via one path and return via a different path.
What are Switching Loops?
An issue with how STP is configured
Spanning Tree Protocol (STP)
What are Routing Loops?
Formed when an error occurs in the operation of the routing algortihm and creates a circular route amongst a group of network devices.
Caused by logical L3 circular connections that may exist in routing
What is a Rogue DHCP Server?
A DHCP server on a network which is not under the administrative control of the network administrators.
What is a DHCP Scope Exhaustion?
Pccurs when the DHCP server runs out of valid IPs to assign to the clients requesting access on the network.
What is a Missing Route?
When a router cannot reach a destination because there is a missing route in the routing table.
What is a Low Optical Link Budget?
A calculation that considers all the anticipated losses along the length of a fiber optic connection
Happens due to the distance of the cable or damage caused to the cable
What could be the cause of some Certificate Issues? List at least 2 of the 3
- Digital certificate is not signed by a trusted certificate authority
- It has already expired
- The server didn’t have a certificate associated with a trusted route certificate
What is a Host-Based Firewall?
Runs on an individual computer or device connected to the network to protect that one device.
What is a Network-Based Firewall?
Deployed in line with the network traffic flow to monitor and filter incoming and outgoing network traffic based on established rule sets.
What could be 3 issues for Host-Based & Network-Based Firewalls?
- Access to protected resources from unprotected networks is not working
- Access to unprotected resources from protected networks is not working
- Access to the firewall and its configurations is not working
What is does a DNS do?
Matches domain names with the corresponding IP addresses used by a server.
What could be 4 issues with DNS?
- Connectivity between client and DNS server
- A records and CNAME records not properly created
- High CPU usage (increases latency, jitter, and packet loss)
- Time to Live (TTL) is not set correctly
What does NTP do?
Allows synchronization of system clocks between different layers of a hierarchical, semi-layered system of time sources.
What could be 3 issues for NTP?
- Packets are not received
- Packets are not processed
- Errors or packet loss
What could be a Licensed Feature Issue?
People who use the things and install the devices are not the same ones who are empowered to make purchasing decisions
What are 2 challenges with a BYOD policy?
- Decrease in capital expenditures
- Increase in operational expenditures
What are some Network Performance Issues? Name at least 3
- High CPU usage
- High bandwidth usage
- Poor connectivity
- Network malfunction
- DNS problems
How would one fix a high CPU usage problem in the network?
To upgrade the network devices to more powerful ones such as enterprise class routers and firewalls.
Or simplify the processing load
How would one fix a high bandwidth usage problem in the network?
Increase the bandwidth size by paying more to your ISP or do a network flow analysis and determine what sites and traffic types are being used by clients.
How would one fix a poor connectivity problem in a network?
Check the cables and test them one by one
Use a cable tester for twisted pair/A fiber light meter for fiber optic
What could be the cause for a network malfunction?
By using old or outdated network operating systems
