CompTIA Network+ · N10-009
Objective 5.5: Given a scenario, troubleshoot common network service issues
Practice questions for Network+ objective 5.5, “Given a scenario, troubleshoot common network service issues.” Every question is original, written to the N10-009 exam objectives, and comes with a full explanation — answer them below to see instant grading.
This objective sits in Domain 5.0: Network Troubleshooting, which is about 18% of the exam — so mastering it moves your readiness score meaningfully.
1.After a server migration, some users can reach the new server while others still connect to the old one. Both groups have correct DNS server settings. What is the most likely explanation?
2.A DHCP client on a remote subnet is not receiving IP addresses from the central DHCP server. Clients on the DHCP server's local subnet obtain addresses without issue. What is the most likely cause?
3.A DNS administrator is investigating why external users cannot resolve the company's public-facing mail server hostname. An nslookup query to the internal DNS server returns the correct IP, but an nslookup directed at a public DNS server (8.8.8.8) returns no result. What is the most likely cause?
4.A user attempts to access an HTTPS website and receives a browser error: "Your connection is not private — NET::ERR_CERT_DATE_INVALID." What type of certificate error is this?
5.A user running a VPN client can connect to the VPN but cannot reach internal network resources after connecting. Other VPN users have no issues. The user's VPN client shows a valid internal IP address assigned. What is the most likely cause?
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