The issue is clearly related to DNS resolution, as IP-based connections succeed but domain name-based ones fail.
D). dig (Domain Information Groper) is a DNS lookup tool used to troubleshoot DNS problems by querying name servers directly.
Other tools are less relevant here:
A). tcpdump is a packet analyzer and is more advanced for deeper traffic analysis.
B). tracert is used to trace the route to a destination, not ideal for DNS issues.
C). nmap is a port scanner and network mapper, not for resolving DNS problems.
# Reference:
CompTIA Network+ N10-009 Official Objectives: 5.1 - Given a scenario, use the appropriate network troubleshooting tools.