ACSP Troubleshooting and Networking 4 — Questions and Answers
Question 1: A user reports their Mac connects to Wi-Fi but websites won't load. Which tool should you use first to verify DNS resolution?
- Network Utility's Ping tab
- Terminal with the 'nslookup' or 'dig' command (Correct answer)
- System Information > Network
- Wireless Diagnostics > Scan
Correct answer: Terminal with the 'nslookup' or 'dig' command
Running 'nslookup' or 'dig' in Terminal directly tests whether DNS is resolving hostnames to IP addresses, pinpointing DNS as the failure point.
Question 2: Which macOS feature allows you to create a network location that automatically switches proxy settings when moving between office and home networks?
- VPN On Demand
- Network Locations in System Settings > Network (Correct answer)
- Wi-Fi preferred networks list
- Content Caching service
Correct answer: Network Locations in System Settings > Network
Network Locations let users save distinct sets of network settings (including proxies) and switch between them manually or via scripts.
Question 3: A MacBook Pro running macOS Ventura shows a self-assigned IP address (169.254.x.x). What is the most likely cause?
- The DHCP server is unreachable or not responding (Correct answer)
- The Mac's firewall is blocking DHCP traffic
- Bluetooth is interfering with Wi-Fi on 2.4 GHz
- The user's router has MAC address filtering enabled
Correct answer: The DHCP server is unreachable or not responding
A 169.254.x.x address is an APIPA (Automatic Private IP Addressing) address assigned by macOS when it cannot obtain a lease from a DHCP server.
Question 4: When troubleshooting a suspected hardware issue on a Mac, which key combination boots into Apple Diagnostics on Apple silicon Macs?
- Hold D during startup
- Hold and continue holding the power button until startup options appear, then select the Diagnostics icon (Correct answer)
- Hold Option-D during startup
- Hold Command-D during startup
Correct answer: Hold and continue holding the power button until startup options appear, then select the Diagnostics icon
On Apple silicon Macs, you hold the power button until startup options appear, then select the diagnostics option; the D key shortcut applies only to Intel Macs.
Question 5: A user cannot send email but can receive it. The outgoing mail server shows a connection error. Which port should you verify is not blocked by their ISP or firewall?
- Port 25 or 587 (SMTP) (Correct answer)
- Port 993 (IMAP over SSL)
- Port 443 (HTTPS)
- Port 110 (POP3)
Correct answer: Port 25 or 587 (SMTP)
SMTP uses ports 25 and 587 for sending mail; many ISPs block port 25 to prevent spam, so port 587 with authentication is the standard alternative.
Question 6: Which command-line tool displays the routing table on macOS to help diagnose why traffic is being sent to the wrong gateway?
- ifconfig
- netstat -rn (Correct answer)
- arp -a
- ipconfig getpacket en0
Correct answer: netstat -rn
'netstat -rn' prints the kernel routing table, showing destination networks, gateways, and interface assignments without performing DNS lookups.
Question 7: A technician uses Wireless Diagnostics on macOS. Which tab shows a real-time graph of signal quality and noise for the connected network?
- Scan
- Info
- Performance (Correct answer)
- Monitor
Correct answer: Performance
The Performance tab in Wireless Diagnostics plots RSSI (signal), noise, and transmit rate over time, making it ideal for spotting intermittent signal issues.
ACSP Troubleshooting and Networking 4
A user reports their Mac connects to Wi-Fi but websites won't load.
Which tool should you use first to verify DNS resolution?