Linux Labs· Networking and Secure AdministrationLab 24 of 37

DNS Client Resolution and Lookup Troubleshooting

The client cannot find the internal app because its resolver points at a dead address and someone left a hosts-file override behind. Fix it through NetworkManager, then read the difference between a wrong answer, no answer, and NXDOMAIN.

  • Intermediate
  • 35 min
  • Not rated yet
  • Free
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In this moduleNetworking and Secure Administration

  1. Inspect IPv4, IPv6, Routes, and Sockets30 min
  2. Persistent NetworkManager Configuration35 min
  3. DNS Client Resolution and Lookup TroubleshootingYou are here
  4. firewalld Zones and Least-Privilege Access35 min
  5. Configure and Operate an SSH Server35 min
  6. SSH Keys and Access Hardening35 min
  7. SFTP and Verified File Synchronization35 min
  8. Bastion Access and Restricted SSH Forwarding40 min