* Definition of a Rogue DHCP Server:
* A rogue DHCP server is an unauthorized DHCP server on a network, which can assign IP addresses to devices without proper control, leading to IP address conflicts.
* Impact of a Rogue DHCP Server:
* IP Address Conflicts:Multiple devices may receive the same IP address from different DHCP servers, causing network connectivity issues.
* Network Disruption:Devices may be assigned incorrect network configuration settings, disrupting network services and connectivity.
* Comparison with Other Attacks:
* DNS poisoning:Alters DNS records to redirect traffic to malicious sites, but does not cause IP address conflicts.
* Social engineering:Involves manipulating individuals to gain unauthorized access or information, not directly related to IP address conflicts.
* Denial-of-service (DoS):Floods a network or service with excessive traffic to disrupt operations, but does not cause duplicate IP addresses.
* Prevention and Detection:
* Implement network access control measures to prevent unauthorized devices from acting as DHCP servers.
* Use DHCP snooping on switches to allow DHCP responses only from authorized DHCP servers.
References:
* CompTIA Network+ study materials on network security threats and mitigation techniques.

Disabling unused ports prevents unauthorized access and reduces the attack surface by ensuring that no inactive or unmonitored entry points are available for exploitation. Changing default passwords is critical for security because default credentials are widely known and can easily be exploited by attackers. These techniques are fundamental steps in hardening devices against unauthorized access and ensuring network security. References: CompTIA Network+ Exam Objectives and official study guides.

A warm site typically has a full infrastructure ready, but it lacks the most up-to-date data or is not immediately operational. It requires some configuration or data restoration to become fully functional.

Port 587 is the standard default port for sending email (SMTP) with TLS encryption, which is used to secure email transmissions between mail servers or between clients and mail servers. Allowing traffic over port 587 enables secure email sending while maintaining standard protocol usage. (Reference: CompTIA Network+ Study Guide, Chapter on Ports and Protocols)

Quality of Service, or QoS, is used when implementing VoIP phones because voice traffic is sensitive to delay, jitter, and packet loss. QoS allows network administrators to classify and prioritize traffic so that real- time voice packets receive preferential treatment over less time-sensitive traffic such as file downloads, backups, or general web browsing. This helps maintain call quality, reduce dropped audio, and improve the user experience during periods of network congestion.
The CompTIA Network+ N10-009 objectives include traffic management, network performance, and services that require prioritization. VoIP is one of the most common examples of a service that benefits from QoS because voice communication must be delivered consistently and in sequence.
A VPN provides secure encrypted connectivity but does not inherently prioritize voice traffic. A CDN distributes content closer to users, typically for web or media delivery, and is not specifically used to implement VoIP phones. TTL, or Time to Live, is a packet field that helps prevent packets from circulating indefinitely in a network. Therefore, QoS is the correct answer for VoIP implementation.