WEBVTT

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<v ->In this section of the course,</v>

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we are going to discuss

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troubleshooting network infrastructure.

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The troubleshooting network infrastructure section

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of the course focuses on Domain Three, security engineering,

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specifically Objective 3.3,

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which states that given a scenario,

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you must be able to troubleshoot

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complex network infrastructure security issues.

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Effective troubleshooting of network infrastructure

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is vital for maintaining a secure

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and efficient digital environment,

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quickly identifying and resolving issues is essential

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to ensure system availability and protect data integrity.

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Misconfigurations and security vulnerabilities

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can pose significant threats

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to both availability and data protection.

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Therefore, comprehensive monitoring through analysis

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and a deep understanding of potential vulnerabilities

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are critical to safeguarding network

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and operational security.

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As we go through this section,

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we will cover many topics related

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to troubleshooting network infrastructure,

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including observability, network errors,

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network misconfiguration, intrusion prevention system,

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and intrusion detection system issues, alert analysis,

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Domain Name System security, email security, network issues,

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cryptographic issues, and public key infrastructure issues.

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First, we will look at observability.

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Observability is the ability to monitor, understand,

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and diagnose the internal states

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and performance of a system based on the data it produces.

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Observability concepts include monitoring,

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understanding, and diagnosing.

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Monitoring involves continuously collecting data

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from various network components.

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These components may include traffic patterns,

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error rates, and system logs.

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Analysis is then used to track

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the network's normal behaviors,

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potential issues, and anomalies.

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This analysis can provide an understanding and insights

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into the underlying causes of problems.

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Next, diagnosis is used to locate the exact source

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of a problem, enabling targeted troubleshooting

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and resolution.

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For example, by monitoring network traffic

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and understanding the patterns,

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an IT team may diagnose a specific misconfiguration

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causing latency issues.

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This recognition and diagnosis can enable the team

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to quickly resolve the problem

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and restore optimal network performance.

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Next, we will explore network errors.

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Network errors are issues that disrupt the normal flow

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of data across a network.

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Network errors often occur due to faults in configuration,

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hardware or software.

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Network error source types include switching errors,

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routing errors, as well as a virtual private network

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and tunnel errors.

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Switching errors occur when data packets

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are misdirected or dropped.

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Switching errors may be due to the result

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of incorrect virtual local area network,

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or VLAN configurations, or switch port failures.

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Routing errors are when incorrect or inefficient paths

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are chosen for data transmission across networks.

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Routing errors can be caused by misconfigured routing tables

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or protocol failures.

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Finally, virtual private network and tunnel errors

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are failures in establishing

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or maintaining secure connections between networks.

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Virtual private network and tunnel errors

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are often due to incorrect settings,

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expired certifications, or issues with encryption protocols.

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For example, if users experience connectivity issues

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when accessing resources through a virtual private network,

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troubleshooting might reveal a routing error combined

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with a virtual private network configuration issue,

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both of which need to be resolved

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to restore seamless and secure network access.

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After that, we will look at network misconfigurations.

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Network misconfigurations include errors

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or incorrect settings within network devices

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that can lead to performance issues,

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security vulnerabilities, or connectivity failures.

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Network misconfiguration concepts

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include unsecured routing and configuration drift.

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Unsecured routing occurs when routing protocols

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or configurations lack proper security measures

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such as authentication or encryption.

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In this way, unsecured routing makes the network

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vulnerable to attacks, like route hijacking or spoofing.

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Configuration drift is the gradual

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and often unnoticed changes in network configuration

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over time.

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These changes can lead to inconsistencies, reduced security,

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and unexpected network behavior.

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For example, an organization might identify

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that an outdated and insecure routing protocol,

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such as the Routing Information Protocol, or RIP,

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has been inadvertently left active

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due to configuration drift.

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This oversight could expose the network to vulnerabilities

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like route injection attacks or spoofing,

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where an attacker could manipulate the routing tables

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to redirect traffic.

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Immediate remediation would involve deactivating

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the insecure protocol,

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replacing it with a more secure alternative like OSPF,

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or the Open Shortest Path First protocol,

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with authentication enabled,

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and implementing automated configuration management tools

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to prevent such drift in the future.

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Next, we will explore intrusion prevention system

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and intrusion detection system issues.

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Intrusion prevention system

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and intrusion detection system issues

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involve challenges related to the correct deployment,

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configuration, and effectiveness of these security system.

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Intrusion prevention system

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and intrusion detection system issues

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include poor placement, lack of rules,

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and rule misconfiguration.

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Placement refers to where the intrusion prevention system

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or intrusion detection system is located within the network.

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An incorrect placement can lead to either missed threats

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or unnecessary alerts.

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Next, a lack of rules

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means that the intrusion prevention system

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or intrusion detection system

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is not equipped with the necessary policies or signatures

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to identify potential threats.

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Finally, rule misconfigurations occur when the rules

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that define the intrusion prevention system

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or intrusion detection system should flag as suspicious

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are set incorrectly.

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Rule misconfigurations can lead to either too many,

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or too few alerts.

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For example, if an intrusion prevention system

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is deployed without a proper rule set

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for the specific traffic patterns of the network,

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it might fail to detect data exfiltration attempts

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using encrypted traffic.

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Alternatively, if the intrusion prevention system

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is configured to overly aggressive rules,

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it could mistakenly block legitimate

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business critical applications,

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leading to unnecessary network disruption

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and operational delays.

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Following that, we will look at alert analysis.

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Alert analysis is reviewing and interpreting security alerts

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to distinguish between genuine threats and benign activity.

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Alert analysis concepts include false positives

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and false negatives.

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False positives occur when a system incorrectly flags

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harmless activity as a security threat.

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False positives lead to unnecessary alarms

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and wasted resources investigating non-issues.

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False negatives on the other hand,

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happen when a system fails to detect real security threats.

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False negatives allow malicious activities

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to go unnoticed and unmitigated.

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So, effective alert analysis is crucial

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for accurately identifying genuine security threats,

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while minimizing the impact of false positives

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and false negatives on resource allocation

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and threat detection.

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Then we will explore Domain Name System, or DNS security.

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Domain Name System security

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is used to protect the system from attacks

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and misconfigurations that could disrupt

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or manipulate network traffic.

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Domain Name System security concepts

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include Domain Name System Security Extensions, or DNSSEC,

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zone transfers, Domain Name System poisoning,

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and sinkholing.

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Domain Name System Security Extensions

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add a layer of security to the name resolution process

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by digitally signing Domain Name System data

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to ensure its integrity and authenticity.

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In this way, Domain Name System Security Extensions

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prevent attackers from tampering

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with Domain Name System responses.

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Next, zone transfers are a normal and expected mechanism

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used to replicate Domain Name System databases

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across servers.

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However, if zone transfers are not properly secured,

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they can be exploited to gain unauthorized access

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to Domain Name System data.

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Next, Domain Name System poisoning, or cache poisoning,

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is an attack where false Domain Name System data

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is injected into a Domain Name System resolver's cache.

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This false Domain Name System data may redirect users

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who conduct valid queries to malicious sites.

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Finally, sinkholing is a defense technique

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that redirects malicious traffic,

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such as that resulting from Domain Name System poisoning,

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to a safe destination for analysis or mitigation.

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In practice,

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implementing Domain Name System Security Extensions

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can prevent Domain Name System poisoning

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by ensuring that Domain Name System responses

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are authenticated.

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While sinkholing can mitigate the impact

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of any successful attack

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by diverting malicious traffic

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away from its intended target.

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Next, we will explore email security.

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Email security protects email communications from threats

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like phishing, spoofing, and unauthorized access.

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Email security is implemented by ensuring the authenticity,

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integrity and confidentiality of messages.

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Email security concepts include Sender policy Framework,

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or SPF, Domain Keys Identified Mail, or DKIM,

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Domain-based Message Authentication Reporting

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and Conformance, or DMARC,

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and Secure/Multipurpose Internet Mail Extensions, or S/MIME.

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Sender Policy Framework is an email validation protocol

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that allows domain owners to specify which mail servers

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are permitted to send emails on their behalf,

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preventing email spoofing.

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Domain Keys Identified Mail adds a digital signature

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to emails, allowing recipients to verify

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that the message has not been altered,

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and that it truly comes from the legitimate sender.

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Domain-based Message Authentication Reporting

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and Conformance, or DMARC,

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provides a framework for email authentication

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and policy enforcement

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to protect against email-based attacks

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based on the results of Sender Policy Framework

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and Domain Keys Identified Mail checks.

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Secure/Multipurpose Internet Mail Extensions, or S/MIME,

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enhances email security by enabling encryption

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and digital signatures in email messages.

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Secure/Multipurpose Internet Mail Extensions

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ensure that only the intended recipient

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can read the content of a message,

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and that the message itself has not been tampered with.

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For example, by implementing Sender Policy Framework

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to verify sending mail servers,

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Domain Keys Identified Mail to ensure email integrity,

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and Domain-based Message Authentication Reporting

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and Conformance to enforce policies

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and report fraudulent activity,

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an organization can significantly reduce the risk

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of email spoofing.

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Additionally, using Secure/Multipurpose Internet

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Mail Extensions to encrypt sensitive emails

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ensures that even if a message is intercepted,

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the contents remain secure and accessible

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only to the intended recipient,

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providing a comprehensive end-to-end protection

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for email communications.

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Then we will explore network issues.

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Network issues include problems that disrupt the normal flow

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of network data and affect connectivity,

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performance, or security.

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Network issues include Network Access Control List issues,

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resource exhaustion,

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and Distributed Denial of Service attacks.

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Network Access Control List issues arise

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when incorrectly configured rules

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allow inappropriate network traffic,

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or block legitimate network traffic.

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Resource exhaustion is the depletion of critical resources

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like bandwidth, memory, or processing power.

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Resource exhaustion is often caused by excessive demand

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or poor resource management,

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and leads to degraded network performance or even outages.

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Distributed Denial of Service attacks

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involve overwhelming a network or service

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with a flood of traffic from multiple sources

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with the goal of resource exhaustion,

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and making the targeted services unavailable

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to legitimate users.

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For example, if a Distributed Denial of Service attack

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targets a network improperly configured,

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Network Access Control List might fail

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to block the malicious traffic,

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resulting in resource exhaustion

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and significant network downtime.

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Following that, we will look at cryptographic issues.

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Cryptographic issues are problems related

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to the implementation and functioning of encrypted protocols

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that secure data.

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Cryptographic issues include

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Transport Layer Security errors, cipher mismatches,

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and issues with cryptographic implementation.

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Transport Layer Security or TLS errors,

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occur when there are problems with the negotiation

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or establishment of a secure connection.

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Transport Layer Security errors

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are often due to expired certificates,

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incorrect configurations, or unsupported protocol version.

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Cipher mismatch occurs when the client and server

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cannot agree on a cipher suite

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during the Transport Layer Security handshake,

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leading to a failed or insecure connection.

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A cipher suite is a set of algorithms that define

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how encryption, authentication, and key exchange

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are implemented in a secure communication session.

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Next, issues with cryptographic implementation are flaws

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or vulnerabilities in the way

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that cryptographic algorithms are applied

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and include weak encryption methods

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or improper key management.

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Issues with cryptographic implementation

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can result in data being inadequately protected.

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Finally, we will look at Public Key Infrastructure issues.

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Public Key Infrastructure, or PKI issues,

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are problems related to the management,

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deployment and functioning of the Public Key Infrastructure.

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Public Key Infrastructure issues undermine the security

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of encrypted communications and digital certificates,

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and can include misconfigured Certificate Authorities,

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expired or improperly issued certificates,

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and challenges in the certification revocation process.

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Each of these Public Key Infrastructure issues

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can lead to failures in establishing trust

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between communicating parties.

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Additionally, improper key management or distribution

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can result in unauthorized access or data breaches

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as keys may be compromised or used incorrectly.

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For example, if a certificate expires

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and is not renewed in time,

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clients may be unable to establish secure connections,

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highlighting the need

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for effective Public Key Infrastructure management

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to ensure continuous trust

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and secure communication within the network.

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To finish things off, we'll take a short quiz

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to see what you learned during this section of the course.

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And we will review each of those quiz questions fully

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to ensure you can explain why the right answers were right,

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and the wrong answers were wrong.

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So let's get ready

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to dive into troubleshooting network infrastructure

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in this section of the course.