ACSP Network Services Management 4 — Questions and Answers
Question 1: A user reports that their Mac can browse the web but cannot connect to a local SMB file server by hostname. Pinging the server by IP succeeds. What is the most likely cause?
- DNS is not resolving local hostnames (Correct answer)
- The SMB service is disabled on the server
- The user's firewall is blocking port 80
- The Mac's network location is set to Automatic
Correct answer: DNS is not resolving local hostnames
When IP connectivity works but hostname resolution fails, DNS is not returning the correct local record for that hostname.
Question 2: Which macOS command-line tool can be used to flush the DNS cache?
- networksetup -flushdns
- dscacheutil -flushcache && killall -HUP mDNSResponder (Correct answer)
- ipconfig /flushdns
- nslookup -flush
Correct answer: dscacheutil -flushcache && killall -HUP mDNSResponder
On macOS, flushing the DNS cache requires clearing the local cache with dscacheutil and signaling mDNSResponder to reset.
Question 3: A Mac is configured with a manual IP address but loses network access after another device joins the network. What is the most likely issue?
- The subnet mask is incorrect
- There is an IP address conflict (Correct answer)
- The default gateway has changed
- IPv6 is interfering with IPv4
Correct answer: There is an IP address conflict
When a manually configured IP is also assigned by DHCP to another device, an IP conflict causes both machines to lose reliable connectivity.
Question 4: In macOS, where can an administrator configure a Mac to use a specific DNS server for a particular network interface?
- System Settings > General > Sharing
- System Settings > Network > [Interface] > Details > DNS (Correct answer)
- Terminal using the networksetup command only
- Keychain Access > Network Passwords
Correct answer: System Settings > Network > [Interface] > Details > DNS
The DNS tab within an interface's Details pane in Network settings allows per-interface DNS server configuration.
Question 5: A Mac using Wi-Fi shows a self-assigned IP address (169.254.x.x). What does this indicate?
- The Mac is connected to a guest network
- The DHCP server did not respond (Correct answer)
- IPv6 is the primary protocol in use
- The wireless password is incorrect
Correct answer: The DHCP server did not respond
A 169.254.x.x address is an APIPA address assigned by the OS when DHCP lease acquisition fails.
Question 6: Which protocol does macOS use to discover services like printers and file shares on a local network without requiring a DNS server?
- LDAP
- Bonjour (mDNS) (Correct answer)
- WINS
- NetBIOS
Correct answer: Bonjour (mDNS)
Bonjour uses multicast DNS (mDNS) over port 5353 to advertise and discover services on the local subnet without a central DNS server.
Question 7: An IT administrator needs to test whether TCP port 443 is open on a remote server from a Mac. Which command is most appropriate?
- ping -p 443 server.example.com
- traceroute server.example.com 443
- nc -zv server.example.com 443 (Correct answer)
- nslookup server.example.com 443
Correct answer: nc -zv server.example.com 443
The netcat (nc) command with -zv flags performs a port scan verbosely without sending data, confirming whether TCP port 443 is open.
ACSP Network Services Management 4
A user reports that their Mac can browse the web but cannot connect to a local SMB file server by hostname.
Pinging the server by IP succeeds.
What is the most likely cause?