CompTIA N10-008 Exam

Port 5900 is the default port used by Virtual Network Computing (VNC), a graphical desktop-sharing system that allows remote access to another computer's screen, keyboard and mouse1. VNC is one of the tools that can be used for remote troubleshooting of servers with high CPU usage, as it enables the technician to see the server's desktop and perform actions on it. Port 5900 is also one of the ports listed in the CompTIA Network+ N10-008 exam objectives under the section '1.4 Given a scenario, use appropriate software tools to troubleshoot connectivity issues'2.

The other ports are not commonly used for remote access. Port 443 is used for Hypertext Transfer Protocol Secure (HTTPS), a secure version of HTTP that encrypts the communication between a web browser and a web server3. Port 3321 is used for Telepathy Broker Service, a service that provides communication between applications and telephony devices4. Port 8080 is used for HTTP Alternate, an alternative port for HTTP that is often used by web servers for testing or proxy purposes5.

Reference

1: Port 5900: What Is It Used for & How to Open It for RDP

2: Network+ (Plus) Certification | CompTIA IT Certifications

3: [What is HTTPS? - Definition from WhatIs.com]

4: [Telepathy Broker Service - Port 3321 - TCP/UDP]

5: [What is Port 8080? Why do some processes use this port?]

An extended service set (ESS) is a type of SSID that allows multiple access points (APs) to share the same SSID and provide seamless roaming for wireless clients. An ESS consists of two or more basic service sets (BSSs), which are individual APs with their own SSIDs. A distribution system (DS), such as a wired Ethernet LAN, connects the BSSs and enables data transfer between them. A wireless client can associate with any AP in the ESS and move from one BSS to another without losing connectivity or reauthenticating.

CompTIA Network+ N10-008 Certification Exam Objectives, page 51

CompTIA Network+ Cert Guide: Wireless Networking, page 12

An extended service set (ESS) is a type of SSID that allows multiple access points (APs) to share the same SSID and provide seamless roaming for wireless clients. An ESS consists of two or more basic service sets (BSSs), which are individual APs with their own SSIDs. A distribution system (DS), such as a wired Ethernet LAN, connects the BSSs and enables data transfer between them. A wireless client can associate with any AP in the ESS and move from one BSS to another without losing connectivity or reauthenticating.

CompTIA Network+ N10-008 Certification Exam Objectives, page 51

CompTIA Network+ Cert Guide: Wireless Networking, page 12

DHCP exhaustion is a situation where the DHCP server runs out of available IP addresses to assign to clients. This can happen due to misconfiguration, malicious attacks, or high demand. When a client requests an IP address from the DHCP server and does not receive a response, it may resort to using an APIPA address, which is a self-assigned address in the range of 169.254.0.1 to 169.254.255.254. APIPA addresses are only valid for local communication and cannot access the internet or other networks. Therefore, a workstation showing an APIPA address indicates that it failed to obtain a valid IP address from the DHCP server, most likely due to DHCP exhaustion