Explain the process of DNS resolution

 Theme: Networking Protocols  Role: Network Engineer  Function: Technology

  Interview Question for Network Engineer:  See sample answers, motivations & red flags for this common interview question. About Network Engineer: Designs and maintains computer networks. This role falls within the Technology function of a firm. See other interview questions & further information for this role here

 Sample Answer 


  Example response for question delving into Networking Protocols with the key points that need to be covered in an effective response. Customize this to your own experience with concrete examples and evidence

  •  Overview of DNS resolution: DNS resolution is the process of converting a domain name into an IP address. It involves several steps to ensure successful resolution
  •  Step 1: Local DNS cache lookup: The client checks its local DNS cache to see if it already has the IP address for the requested domain name. If found, the resolution process ends
  •  Step 2: Recursive DNS server lookup: If the IP address is not found in the local DNS cache, the client sends a query to a recursive DNS server. This server is responsible for resolving the domain name on behalf of the client
  •  Step 3: Root DNS server lookup: The recursive DNS server starts the resolution process by querying the root DNS servers. These servers maintain a list of authoritative DNS servers for top-level domains (TLDs)
  •  Step 4: TLD DNS server lookup: Based on the response from the root DNS server, the recursive DNS server queries the TLD DNS server responsible for the specific domain extension (e.g., .com, .org)
  •  Step 5: Authoritative DNS server lookup: The TLD DNS server provides the IP address of the authoritative DNS server for the requested domain. The recursive DNS server then queries the authoritative DNS server
  •  Step 6: IP address resolution: The authoritative DNS server responds with the IP address of the requested domain. The recursive DNS server caches this information and sends it back to the client
  •  Step 7: Client receives IP address: Finally, the client receives the IP address from the recursive DNS server and can establish a connection with the desired domain using the obtained IP address

 Underlying Motivations 


  What the Interviewer is trying to find out about you and your experiences through this question

  •  Technical knowledge: Assessing your understanding of DNS resolution process
  •  Problem-solving skills: Evaluating your ability to troubleshoot DNS issues
  •  Communication skills: Assessing your ability to explain complex technical concepts in a clear and concise manner

 Potential Minefields 


  How to avoid some common minefields when answering this question in order to not raise any red flags

  •  Lack of understanding: Providing a vague or incorrect explanation of DNS resolution process
  •  Skipping important steps: Leaving out crucial steps like DNS query, recursive resolution, or caching
  •  Inability to troubleshoot: Failing to mention troubleshooting techniques like checking DNS server settings or using nslookup or dig commands
  •  Not addressing security concerns: Neglecting to mention DNS security measures like DNSSEC or DNS filtering
  •  Poor communication skills: Using technical jargon without explaining it or providing a clear and concise explanation

 Related

  Other questions asked for the Network Engineer in Technology function. View details for the Network Engineer here