DNS - Domain Name System ========================== .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What is DNS?** DNS stands for Domain Name System. It’s like the phonebook of the internet. When you type a website name like www.example.com into your browser, DNS translates that name into an IP address (like 192.0.2.1) so your computer can find and connect to the correct website. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Why is DNS important?** Computers use IP addresses to identify each other on the internet. Humans prefer easy-to-remember names (like google.com) instead of numbers. DNS makes it possible to use names instead of IP addresses. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How DNS works (in simple steps):** * You enter a website name in your browser. * Your device asks a DNS server to find the matching IP address. * The DNS server replies with the IP address. * Your browser connects to that IP address and loads the website. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Where is DNS used?** Web Browsing, Email Services, Mobile Apps, Cloud Services, Enterprise Networks, IoT Devices, CDNs (Content Delivery Networks) and everywhere on the internet to translate names into IP addresses, enabling communication between devices and services. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Which OSI layer does this protocol belong to?** DNS is a service that applications (like web browsers or email clients) use to resolve domain names into IP addresses. Since it directly interacts with user-level applications, it belongs to the Application Layer. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow Topics in this section, * :ref:`Learnings in this section ` * :ref:`Terminology ` * :ref:`Version Info ` * :ref:`DNS Version&RFC Details ` * :ref:`DNS Basic Setup on Ubuntu using IPv4 ` * :ref:`DNS Basic Setup on Ubuntu using IPv6 ` * :ref:`DNS Protocol Packet Details ` * :ref:`DNS Usecases ` * :ref:`DNS Basic Features ` * :ref:`DNS Feature : Name Resolution ` * :ref:`DNS Feature : Record Types ` * :ref:`DNS Feature : Caching ` * :ref:`DNS Feature : Recursive & Iterative Queries ` * :ref:`DNS Feature : Zone Management ` * :ref:`DNS Feature : Delegation ` * :ref:`DNS Feature : Reverse DNS Lookup ` * :ref:`DNS Feature : Security Extensions(DNSSEC) ` * :ref:`DNS Feature : Load Balancing ` * :ref:`DNS Feature : Redundancy & Failover ` * :ref:`Reference links ` .. _DNS_step1: .. tab-set:: .. tab-item:: Learnings in this section * In this section, you are going to learn .. _DNS_step2: .. tab-set:: .. tab-item:: Terminology * Terminology .. _DNS_step3: .. tab-set:: .. tab-item:: Version Info * Version Info .. _DNS_step5: .. tab-set:: .. tab-item:: DNS Version&RFC Details .. csv-table:: :file: ./DNS/DNS_Version_and_RFC_Details.csv :widths: 10,10,10,30 :header-rows: 1 .. _DNS_step20: .. tab-set:: .. tab-item:: DNS Basic Setup on Ubuntu using IPv4 **Setup** .. _DNS_step21: .. tab-set:: .. tab-item:: DNS Basic Setup on Ubuntu using IPv6 **Setup** .. _DNS_step6: .. tab-set:: .. tab-item:: DNS Protocol Packet Details **DNS Query Packet** .. csv-table:: :file: ./DNS/DNS_packetdetails1.csv :widths: 10,20,30,10 :header-rows: 1 **DNS Response Packet** .. csv-table:: :file: ./DNS/DNS_packetdetails2.csv :widths: 10,20,30,10 :header-rows: 1 .. _DNS_step7: .. tab-set:: .. tab-item:: DNS Usecases .. csv-table:: :file: ./DNS/DNS_Use_Cases.csv :widths: 10,20,30 :header-rows: 1 .. _DNS_step8: .. tab-set:: .. tab-item:: DNS Basic Features .. csv-table:: :file: ./DNS/DNS_Basic_Features.csv :widths: 10,10,30 :header-rows: 1 .. _DNS_step9: .. tab-set:: .. tab-item:: DNS Feature : Name Resolution **Name Resolution - Testcases** .. csv-table:: :file: ./DNS/DNS_Feature1_Name_Resolution_Test_Cases.csv :widths: 10,10,30,20 :header-rows: 1 .. _DNS_step10: .. tab-set:: .. tab-item:: DNS Feature : Record Types **Record Types - Testcases** .. csv-table:: :file: ./DNS/DNS_Feature2_Record_Types_Test_Cases.csv :widths: 10,10,30,20 :header-rows: 1 .. _DNS_step11: .. tab-set:: .. tab-item:: DNS Feature : Caching **Caching - Testcases** .. csv-table:: :file: ./DNS/DNS_Feature3_Caching_Test_Cases.csv :widths: 10,10,30,20 :header-rows: 1 .. _DNS_step12: .. tab-set:: .. tab-item:: DNS Feature : Recursive & Iterative Queries **Recursive & Iterative Queries - Testcases** .. csv-table:: :file: ./DNS/DNS_Feature4_Recursive_and_Iterative_Queries_Test_Cases.csv :widths: 10,10,30,20 :header-rows: 1 .. _DNS_step13: .. tab-set:: .. tab-item:: DNS Feature : Zone Management **Zone Management - Testcases** .. csv-table:: :file: ./DNS/DNS_Feature5_Zone_Management_Test_Cases.csv :widths: 10,10,30,20 :header-rows: 1 .. _DNS_step14: .. tab-set:: .. tab-item:: DNS Feature : Delegation **Delegation - Testcases** .. csv-table:: :file: ./DNS/DNS_Feature6_Delegation_Test_Cases.csv :widths: 10,10,30,20 :header-rows: 1 .. _DNS_step15: .. tab-set:: .. tab-item:: DNS Feature : Reverse DNS Lookup **Reverse DNS Lookup - Testcases** .. csv-table:: :file: ./DNS/DNS_Feature7_Reverse_DNS_Lookup_Test_Cases.csv :widths: 10,10,30,20 :header-rows: 1 .. _DNS_step16: .. tab-set:: .. tab-item:: DNS Feature : Security Extensions (DNSSEC) **Security Extensions (DNSSEC) - Testcases** .. csv-table:: :file: ./DNS/DNS_Feature8_Security_Extensions_DNSSEC_Test_Cases.csv :widths: 10,10,30,20 :header-rows: 1 .. _DNS_step17: .. tab-set:: .. tab-item:: DNS Feature : Load Balancing **Load Balancing - Testcases** .. csv-table:: :file: ./DNS/DNS_Feature9_Load_Balancing_Test_Cases.csv :widths: 10,10,30,20 :header-rows: 1 .. _DNS_step18: .. tab-set:: .. tab-item:: DNS Feature : Redundancy & Failover **Redundancy & Failover - Testcases** .. csv-table:: :file: ./DNS/DNS_Feature10_Redundancy_and_Failover_Test_Cases.csv :widths: 10,10,30,20 :header-rows: 1 .. _DNS_step19: .. tab-set:: .. tab-item:: Reference links * Reference links