Lesson 21: Troubleshoot Network Issues

Question 1

What are four common issues that can interrupt network services on a Mac?

Answer 1

Four common issues that interrupt network services on Mac computers are:

1. Ethernet connectivity issues can cause the hardware network interface to become inactive or introduce excessive packet errors.
2. Selection of an improper Wi-Fi network or excessive wireless interference can cause Wi-Fi connectivity issues.
3. DHCP service issues prevent proper TCP/IP configuration.
4. DNS service issues prevent host name resolution.

Question 2

How do network devices acquire and use self-assigned TCP/IP addresses?

Answer 2

If DHCP is specified as the configuration for a TCP/IP connection and no DHCP service is available, the device automatically selects a random IP address in the 169.254.xxx.xxx range.

It checks the local network to ensure that no other network device is using the randomly generated IP address before it applies the IP address.

In most cases, though, this addressing is not normal, and it’s often indicative of a problem with DHCP services.

Question 3

How can you identify the MAC addresses for all the Mac computer’s network interfaces?

Answer 3

You can identify all the MAC addresses for the Mac computer’s network interfaces from the Info pane of Network Utility.

Question 4

How can you verify basic connectivity to another network host?

Answer 4

The Ping tab of Network Utility allows you to test basic connectivity to another network host by sending and then waiting for the return of a ping packet.

Question 5

How can you verify that DNS host name resolution is working?

Answer 5

The Lookup tab of Network Utility allows you to test name resolution against the currently configured DNS server.

Question 6

How can you verify that the system can establish a connection to a remote network host?

Answer 6

The Traceroute tab of Network Utility allows you to verify the connection hops between your Mac and a remote host.