ACSP Troubleshooting and Networking 2

Question 1

What is the 'ping' command used for in macOS network troubleshooting?

Accepted Answer

Ping sends ICMP Echo Request packets to a destination and measures round-trip time; used to verify connectivity, test if a host is reachable, and identify latency or packet loss

Answer

'ping hostname' or 'ping IP_address' sends ICMP Echo Requests and reports replies with round-trip times. No replies = host unreachable or blocking ICMP. High latency or packet loss indicates network issues. Essential first-step connectivity test.

Question 2

A Mac can connect to the local network but cannot reach the internet. What systematic troubleshooting steps should be taken?

Accepted Answer

Test local gateway ping, check DNS resolution, test internet IP ping, verify default route, then check ISP-side issues — narrowing from local to remote systematically

Answer

Systematic network troubleshooting follows the OSI model from local to remote: ping the default gateway (local connectivity), ping 8.8.8.8 (ISP/routing), ping google.com (DNS), check 'networksetup' settings, check router for blocked MAC, verify with another device.

Question 3

What does 'traceroute' show in macOS network diagnostics?

Accepted Answer

Traceroute shows each network hop (router) between the Mac and destination, with latency at each hop — revealing where packets are delayed or dropped along the path

Answer

'traceroute hostname' (or 'traceroute -n IP_address' to skip DNS lookups) sends packets with incrementing TTL values, revealing each router hop with its IP/hostname and round-trip latency — showing exactly where high latency or packet loss occurs along the network path.

Question 4

What is Wireless Diagnostics in macOS and how does a technician access it?

Accepted Answer

Wireless Diagnostics is a built-in macOS tool for analyzing Wi-Fi environment, logging connections, scanning channels, and capturing packets; accessed by Option-clicking the Wi-Fi menu bar icon and selecting 'Open Wireless Diagnostics'

Answer

Wireless Diagnostics (/System/Library/CoreServices/Applications/Wireless Diagnostics.app) is accessed via Option+click on the Wi-Fi menu bar icon. It offers guided troubleshooting, Wi-Fi environment scanning (nearby networks and channels), performance graphs, and packet capture.

Question 5

What does a 'Self-Assigned IP Address' (169.254.x.x) mean on macOS and how should it be resolved?

Accepted Answer

169.254.x.x is an APIPA (Automatic Private IP Addressing) address assigned when DHCP fails; indicates the Mac cannot reach the DHCP server — check cable/Wi-Fi connection, router DHCP status, and try 'Renew DHCP Lease'

Answer

A 169.254.x.x address (APIPA/link-local) is self-assigned by macOS when DHCP fails — the Mac couldn't get an IP from the router. The Mac cannot reach internet or other DHCP-assigned devices until the DHCP issue is resolved.

ACSP - Apple Certified Support Professional Practice Test

ACSP - Apple Certified Support Professional Practice Test

ACSP Troubleshooting and Networking 2