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$ curl repovive.com/roadmaps/network-design/troubleshooting-methodology/dns-problems

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DNS Problems - Troubleshooting Methodology | Network Design | Repovive

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Network Design26 sections · 911 units44h total

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DNS Problems

Name resolution failures

DNS problems are common but easily mistaken for connectivity issues. If you can ping by IP but not by hostname, DNS is the culprit.

Symptoms of DNS issues:

Websites fail by name but work by IP
"Server not found" errors
Slow page loads while waiting for DNS timeout

Common causes:

DNS server unreachable
Incorrect DNS server configured
DNS cache containing stale entries

Diagnostic commands:

nslookup google.com
ipconfig /displaydns
ipconfig /flushdns

Test DNS resolution to both internal and external names.