DNS Troubleshooting
🌐 DNS Troubleshooting | Linux Level-2 Series | Lab 12
Welcome to Lab 12 of the Linux Level-2 Series! In this practical lab, you’ll learn how to troubleshoot DNS issues and configure reliable nameservers—an essential skill for maintaining stable application connectivity.
The xFusionCorp system admins have identified DNS resolution issues on App Server 3 in the Stratos Datacenter. As a temporary fix, you’ll configure Google Public DNS to ensure consistent name resolution.
📌 Lab Objective:
Fix DNS resolution issues by adding public DNS nameservers.
🛠️ Task Requirements:
Server: App Server 3
Add Google Public DNS (IPv4):
8.8.8.8
8.8.4.4
💻 Step-by-Step Commands:
SSH into App Server 3
ssh banner@stapp03
Edit resolv.conf file
sudo vi /etc/resolv.conf
🔧 Add the following lines:
nameserver 8.8.8.8
nameserver 8.8.4.4
Save and exit
🔍 Test DNS Resolution:
ping -c 3 google.com
or
nslookup google.com
✅ Expected Outcome:
DNS resolution issues resolved
Server can resolve domain names successfully
Applications function without DNS-related interruptions
📚 What You’ll Learn in This Video:
How DNS resolution works in Linux
Troubleshooting DNS-related issues
Configuring /etc/resolv.conf
Using public DNS servers like Google DNS
Verifying connectivity and name resolution
Real-world DevOps troubleshooting techniques
🌟 Why This Lab Matters:
DNS is a critical part of any infrastructure. Misconfigured DNS can break applications, APIs, and connectivity. Knowing how to diagnose and fix DNS issues is a must-have skill for DevOps engineers.
🎯 Series: Linux Level-2
Continue mastering Linux with real-world labs focused on system administration, networking, and automation.
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