DNS is a globally distributed database that translates domain names to IP addresses. It consists of a name space organized in a hierarchical tree structure, servers that store data about parts of the name space, and resolvers that query servers to map names to addresses. The resolution process involves recursively querying servers at higher levels, like root and TLD servers, until reaching an authoritative name server that can provide the address. Caching improves performance by storing previous lookups.
DNS is a distributed database that translates hostnames to IP addresses. It operates through a hierarchy of root servers, top-level domain servers, and authoritative name servers. DNS provides additional services like load balancing and mail server aliasing. Queries are resolved through recursive or iterative lookups between clients and servers to map names to addresses.
The Domain Name System (DNS) is a hierarchical distributed naming system for computers, services, or any resource connected to the Internet or a private network. It associates various information with domain names assigned to each of the participating entities. A domain name represents an Internet Protocol (IP) resource ultimately identifiable by a numeric IP address. DNS servers store records that map domain names to IP addresses and vice versa. The DNS hierarchy consists of root name servers at the top, authoritative name servers for top-level domains and their subdomains below them. When a user enters a domain name, the DNS server first checks its cache and if it doesn't find a match, it queries authoritative name servers to resolve the IP address associated with the domain name.
This document provides an overview of the Domain Name System (DNS) in several paragraphs. It begins with an introduction to DNS as a large distributed database that contains domain names and IP addresses. It then discusses the history of DNS and how it evolved from a centralized hosts file to a distributed system. The remainder of the document describes the key components of DNS including the name space, resolvers, name servers, and explains why DNS is needed by covering aspects like scalability, reliability, and dynamic updates.
The document discusses the Domain Name System (DNS) which maps domain names to IP addresses. It describes how DNS works hierarchically with a root server at the top level, below which are generic, country-specific and other domain levels. DNS servers store and distribute this mapping information across multiple computers to avoid a single point of failure. Primary DNS servers store and update zone files mapping domain names to IP addresses, while secondary servers transfer this information from primary servers.
This slide contains details about domain name servers (DNS).
It also contains Resolution of the Name Servers with Domain Name Structure with statistics table. The process of Name resolution is also explained with Recursive and iterative resolution processes.
The document provides an overview of the Domain Name System (DNS). It discusses how DNS works to translate domain names to IP addresses by using a distributed database across multiple server types. DNS implements a hierarchical namespace and resolves domain names through cooperation between local name servers and authoritative name servers. It allows internet resources to be accessed through easy to remember domain names instead of hard to remember IP addresses.
The document discusses the Domain Name System (DNS) and how it works. DNS is an internet directory service that maps hostnames to IP addresses, allowing users to use names instead of numbers. It uses a distributed, hierarchical system of name servers to perform this name resolution in a scalable way. DNS caches mappings for performance, starting queries at the highest level domains and following delegations between servers until the answer is found. DNS has become a major attack vector, so protection of DNS infrastructure and traffic is important.
The document discusses the Domain Name System (DNS). It describes DNS as a hierarchical and distributed database that maps hostnames to IP addresses. DNS uses a tree structure with nodes containing domain names that are read from the node up to the root. The document outlines the key components of DNS including fully and partially qualified domain names, zones, primary and secondary name servers, and the different top-level domains like generic, country, and inverse domains used for name to address and address to name lookups.
DNS is a distributed database that translates hostnames to IP addresses. It operates through a hierarchy of root servers, top-level domain servers, and authoritative name servers. DNS provides additional services like load balancing and mail server aliasing. Queries are resolved through recursive or iterative lookups between clients and servers to map names to addresses.
The Domain Name System (DNS) is a hierarchical distributed naming system for computers, services, or any resource connected to the Internet or a private network. It associates various information with domain names assigned to each of the participating entities. A domain name represents an Internet Protocol (IP) resource ultimately identifiable by a numeric IP address. DNS servers store records that map domain names to IP addresses and vice versa. The DNS hierarchy consists of root name servers at the top, authoritative name servers for top-level domains and their subdomains below them. When a user enters a domain name, the DNS server first checks its cache and if it doesn't find a match, it queries authoritative name servers to resolve the IP address associated with the domain name.
This document provides an overview of the Domain Name System (DNS) in several paragraphs. It begins with an introduction to DNS as a large distributed database that contains domain names and IP addresses. It then discusses the history of DNS and how it evolved from a centralized hosts file to a distributed system. The remainder of the document describes the key components of DNS including the name space, resolvers, name servers, and explains why DNS is needed by covering aspects like scalability, reliability, and dynamic updates.
The document discusses the Domain Name System (DNS) which maps domain names to IP addresses. It describes how DNS works hierarchically with a root server at the top level, below which are generic, country-specific and other domain levels. DNS servers store and distribute this mapping information across multiple computers to avoid a single point of failure. Primary DNS servers store and update zone files mapping domain names to IP addresses, while secondary servers transfer this information from primary servers.
This slide contains details about domain name servers (DNS).
It also contains Resolution of the Name Servers with Domain Name Structure with statistics table. The process of Name resolution is also explained with Recursive and iterative resolution processes.
The document provides an overview of the Domain Name System (DNS). It discusses how DNS works to translate domain names to IP addresses by using a distributed database across multiple server types. DNS implements a hierarchical namespace and resolves domain names through cooperation between local name servers and authoritative name servers. It allows internet resources to be accessed through easy to remember domain names instead of hard to remember IP addresses.
The document discusses the Domain Name System (DNS) and how it works. DNS is an internet directory service that maps hostnames to IP addresses, allowing users to use names instead of numbers. It uses a distributed, hierarchical system of name servers to perform this name resolution in a scalable way. DNS caches mappings for performance, starting queries at the highest level domains and following delegations between servers until the answer is found. DNS has become a major attack vector, so protection of DNS infrastructure and traffic is important.
The document discusses the Domain Name System (DNS). It describes DNS as a hierarchical and distributed database that maps hostnames to IP addresses. DNS uses a tree structure with nodes containing domain names that are read from the node up to the root. The document outlines the key components of DNS including fully and partially qualified domain names, zones, primary and secondary name servers, and the different top-level domains like generic, country, and inverse domains used for name to address and address to name lookups.
The document discusses the Domain Name System (DNS) which maps domain names to IP addresses. DNS uses a client-server model where clients (resolvers) query name servers to lookup addresses. It describes the hierarchical namespace structure and how names are organized into domains with labels separated by dots. Resource records containing domain, type, class and data are stored in distributed databases to map names and addresses. Caching improves performance by storing recent lookups.
The document is a presentation on DNS (Domain Name System) given by Mauood Hamidi for his dissertation. It covers definitions of DNS, different types of DNS servers, tools used for DNS queries, DNS records, how DNS works to resolve domain names to IP addresses, and components of the DNS system like zones, name servers, and security considerations. It aims to provide an overview of the key concepts and functioning of DNS.
The document discusses the Domain Name System (DNS) and its components. It explains what DNS is, how it works to translate domain names to IP addresses, the different record types used in DNS like A, NS, MX records. It describes DNS name servers, resolvers, zones and namespaces. It provides examples of DNS configuration files for both master and slave name servers as well as sample zone files mapping names to IP addresses.
Domain Name System (DNS) is a hierarchical distributed database that contains mappings of domain names to IP addresses. DNS allows easy to remember domain names to be used instead of hard to remember IP addresses. It works by matching domain names to IP addresses through a lookup process involving root servers, top-level domain servers and authoritative name servers. This allows computers all over the world to communicate with each other using domain names.
This document provides an overview of the Domain Name System (DNS). It discusses what DNS is, why names are used instead of IP addresses, and the history and development of DNS. It describes the hierarchical name space and domain system. It also explains different DNS record types like A, CNAME, MX, and NS records. The document discusses recursive and iterative queries, legal users of domains, and security issues with the traditional DNS system. It provides an overview of how DNSSEC aims to address some of these security issues through digital signing of DNS records.
The document discusses the Domain Name System (DNS) which translates human-friendly domain names to IP addresses. It describes DNS as the internet's equivalent of a phone book. DNS uses a hierarchical, domain-based naming scheme and distributed database to implement this naming system. The DNS database contains resource records (RRs) that map domain names to IP addresses and other attributes. There are different types of name servers, including authoritative, caching, primary, and secondary servers that maintain the DNS database and resolve queries. DNS resolution can occur through either recursive or iterative queries to translate names to addresses.
This document provides an overview of the Domain Name System (DNS). It describes how DNS uses domain names to map to IP addresses in a hierarchical structure. Key points include:
- DNS allows users to use domain names like "example.com" instead of numeric IP addresses for easier identification of internet hosts.
- DNS information is stored across multiple name servers to prevent a single point of failure.
- The domain name space is divided into generic, country code, and inverse domains to organize names by usage and map addresses to names.
- Domain names are read from right to left with the top-level domain at the far right, working left through more specific subdomains.
The document discusses the need for and history of the Domain Name System (DNS). It explains that DNS was created to map human-friendly domain names to IP addresses and vice versa. Originally, a single host file contained all name-IP mappings but this became infeasible as the internet grew. DNS addresses this by hierarchically dividing the name space and distributing the mappings across multiple name servers. It uses a tree structure with domains like .com, .edu at the top level and subdomains below. DNS servers are authoritative for different zones and work together to resolve queries through either recursive or iterative queries.
The document discusses the Domain Name System (DNS), which translates domain names to IP addresses and vice versa. It describes the hierarchical structure of DNS with zones, resource records, and name servers. Primary and secondary name servers maintain authoritative data for zones, while caching name servers store previously looked up data to improve performance. The domain name resolution process involves queries to authoritative and caching name servers to map names to addresses.
The document discusses the Domain Name System (DNS), explaining that it is a globally distributed database that translates human-friendly website addresses into computer-friendly IP addresses and vice versa. DNS uses a hierarchical system to organize domain names and resolve queries through recursive or iterative processes, with DNS messages containing header, question, answer, and additional record sections to facilitate name-address mapping.
TCP/IP is a set of communication protocols used to connect devices on the internet and other networks. It has two main protocols - TCP for reliable transmission of data between devices, and IP for addressing devices and routing packets across networks. TCP/IP uses ports to allow multiple applications to run simultaneously on a single device. Routers use IP addressing and routing tables to determine the best path for sending packets between devices on different networks.
DHCP (Dynamic Host Configuration Protocol) is a protocol that automatically provides IP hosts with IP addresses and other configuration information from a DHCP server. It uses UDP and works by having clients broadcast discover messages to locate servers, which respond with offer messages containing IP addresses and configuration options. Servers then acknowledge address assignments, while also allowing reservations of specific addresses and exclusions of certain ranges. Windows Server backs up the DHCP database and configuration every 60 minutes for restoration using the netsh command.
The Domain Name System (DNS) is a hierarchical decentralized naming system for computers, services, or any resource connected to the Internet or a private network. It associates various information with domain names assigned to each of the participating entities. Most prominently, it translates more readily memorized domain names to the numerical IP addresses needed for the purpose of locating and identifying computer services and devices with the underlying network protocols. By providing a worldwide, distributed directory service, the Domain Name System is an essential component of the functionality of the Internet.
HTTP is the application-layer protocol for transmitting hypertext documents across the internet. It works by establishing a TCP connection between an HTTP client, like a web browser, and an HTTP server. The client sends a request to the server using methods like GET or POST. The server responds with a status code and the requested resource. HTTP is stateless, meaning each request is independent and servers do not remember past client interactions. Cookies and caching are techniques used to maintain some state and improve performance.
The Domain Name System (DNS) was invented in 1983 to translate between hostnames that are easy for humans to remember and IP addresses that computers use, through a hierarchical system where each part of a domain name separates levels of delegation down to individual host machines, with top-level domains and country domains at the top level managed by centralized authoritative name servers. DNS uses a distributed database across multiple name servers that can query each other to lookup and cache hostname to IP mappings, using both UDP and TCP protocols to handle queries and full database replication respectively.
This document provides an overview of managing user accounts in a Microsoft Windows Server 2003 environment. It discusses the purpose of user accounts and the authentication process. It also describes how to create and manage local, roaming, and mandatory user profiles. Various methods for creating and modifying user accounts using tools like Active Directory Users and Computers and command line utilities are presented.
The document discusses DNS (Domain Name System) records. It explains that DNS is a hierarchical naming system that maps hostnames to IP addresses. DNS records are the basic data elements that allow DNS servers to perform this mapping. The document describes several important DNS record types including A records, which map hostnames to IPv4 addresses; AAAA records, which map to IPv6 addresses; CNAME records, which map aliases to hostnames; and MX records, which specify mail servers for a domain. It also briefly mentions SOA, PTR, and SRV records along with sources for further information on DNS records.
FTP uses two TCP connections - a control connection on port 21 for sending commands and a data connection on port 20 for transferring files. The control connection maintains state about the user and session and is used to open and close the data connection for individual file transfers. Common FTP commands are used to login with username and password, list directory contents, and get/put files between hosts.
FTP is a protocol for transferring files between a client and server on a network. It defines a client (user) and server model with separate control and data connections to transfer files reliably and efficiently while shielding users from variations in file storage. The control connection uses commands to manage the session and transfer parameters while the data connection handles the actual transfer of files in one of several modes.
DNS, which stands for domain name system, controls your domain name's website and email settings. When visitors go to your domain name, its DNS settings control which company's server it reaches out to.
This document provides an overview of the Domain Name System (DNS) including:
- The DNS uses a globally distributed database to translate human-friendly domain names to computer-friendly IP addresses.
- It has a hierarchical structure with top-level domains like .com and country codes delegated to different name servers, and subdomains can be further delegated.
- DNS name servers store records about their portion of the name space and resolve queries by either responding with records from their cache or by recursively querying other name servers until the answer is found.
The document discusses the Domain Name System (DNS) which maps domain names to IP addresses. DNS uses a client-server model where clients (resolvers) query name servers to lookup addresses. It describes the hierarchical namespace structure and how names are organized into domains with labels separated by dots. Resource records containing domain, type, class and data are stored in distributed databases to map names and addresses. Caching improves performance by storing recent lookups.
The document is a presentation on DNS (Domain Name System) given by Mauood Hamidi for his dissertation. It covers definitions of DNS, different types of DNS servers, tools used for DNS queries, DNS records, how DNS works to resolve domain names to IP addresses, and components of the DNS system like zones, name servers, and security considerations. It aims to provide an overview of the key concepts and functioning of DNS.
The document discusses the Domain Name System (DNS) and its components. It explains what DNS is, how it works to translate domain names to IP addresses, the different record types used in DNS like A, NS, MX records. It describes DNS name servers, resolvers, zones and namespaces. It provides examples of DNS configuration files for both master and slave name servers as well as sample zone files mapping names to IP addresses.
Domain Name System (DNS) is a hierarchical distributed database that contains mappings of domain names to IP addresses. DNS allows easy to remember domain names to be used instead of hard to remember IP addresses. It works by matching domain names to IP addresses through a lookup process involving root servers, top-level domain servers and authoritative name servers. This allows computers all over the world to communicate with each other using domain names.
This document provides an overview of the Domain Name System (DNS). It discusses what DNS is, why names are used instead of IP addresses, and the history and development of DNS. It describes the hierarchical name space and domain system. It also explains different DNS record types like A, CNAME, MX, and NS records. The document discusses recursive and iterative queries, legal users of domains, and security issues with the traditional DNS system. It provides an overview of how DNSSEC aims to address some of these security issues through digital signing of DNS records.
The document discusses the Domain Name System (DNS) which translates human-friendly domain names to IP addresses. It describes DNS as the internet's equivalent of a phone book. DNS uses a hierarchical, domain-based naming scheme and distributed database to implement this naming system. The DNS database contains resource records (RRs) that map domain names to IP addresses and other attributes. There are different types of name servers, including authoritative, caching, primary, and secondary servers that maintain the DNS database and resolve queries. DNS resolution can occur through either recursive or iterative queries to translate names to addresses.
This document provides an overview of the Domain Name System (DNS). It describes how DNS uses domain names to map to IP addresses in a hierarchical structure. Key points include:
- DNS allows users to use domain names like "example.com" instead of numeric IP addresses for easier identification of internet hosts.
- DNS information is stored across multiple name servers to prevent a single point of failure.
- The domain name space is divided into generic, country code, and inverse domains to organize names by usage and map addresses to names.
- Domain names are read from right to left with the top-level domain at the far right, working left through more specific subdomains.
The document discusses the need for and history of the Domain Name System (DNS). It explains that DNS was created to map human-friendly domain names to IP addresses and vice versa. Originally, a single host file contained all name-IP mappings but this became infeasible as the internet grew. DNS addresses this by hierarchically dividing the name space and distributing the mappings across multiple name servers. It uses a tree structure with domains like .com, .edu at the top level and subdomains below. DNS servers are authoritative for different zones and work together to resolve queries through either recursive or iterative queries.
The document discusses the Domain Name System (DNS), which translates domain names to IP addresses and vice versa. It describes the hierarchical structure of DNS with zones, resource records, and name servers. Primary and secondary name servers maintain authoritative data for zones, while caching name servers store previously looked up data to improve performance. The domain name resolution process involves queries to authoritative and caching name servers to map names to addresses.
The document discusses the Domain Name System (DNS), explaining that it is a globally distributed database that translates human-friendly website addresses into computer-friendly IP addresses and vice versa. DNS uses a hierarchical system to organize domain names and resolve queries through recursive or iterative processes, with DNS messages containing header, question, answer, and additional record sections to facilitate name-address mapping.
TCP/IP is a set of communication protocols used to connect devices on the internet and other networks. It has two main protocols - TCP for reliable transmission of data between devices, and IP for addressing devices and routing packets across networks. TCP/IP uses ports to allow multiple applications to run simultaneously on a single device. Routers use IP addressing and routing tables to determine the best path for sending packets between devices on different networks.
DHCP (Dynamic Host Configuration Protocol) is a protocol that automatically provides IP hosts with IP addresses and other configuration information from a DHCP server. It uses UDP and works by having clients broadcast discover messages to locate servers, which respond with offer messages containing IP addresses and configuration options. Servers then acknowledge address assignments, while also allowing reservations of specific addresses and exclusions of certain ranges. Windows Server backs up the DHCP database and configuration every 60 minutes for restoration using the netsh command.
The Domain Name System (DNS) is a hierarchical decentralized naming system for computers, services, or any resource connected to the Internet or a private network. It associates various information with domain names assigned to each of the participating entities. Most prominently, it translates more readily memorized domain names to the numerical IP addresses needed for the purpose of locating and identifying computer services and devices with the underlying network protocols. By providing a worldwide, distributed directory service, the Domain Name System is an essential component of the functionality of the Internet.
HTTP is the application-layer protocol for transmitting hypertext documents across the internet. It works by establishing a TCP connection between an HTTP client, like a web browser, and an HTTP server. The client sends a request to the server using methods like GET or POST. The server responds with a status code and the requested resource. HTTP is stateless, meaning each request is independent and servers do not remember past client interactions. Cookies and caching are techniques used to maintain some state and improve performance.
The Domain Name System (DNS) was invented in 1983 to translate between hostnames that are easy for humans to remember and IP addresses that computers use, through a hierarchical system where each part of a domain name separates levels of delegation down to individual host machines, with top-level domains and country domains at the top level managed by centralized authoritative name servers. DNS uses a distributed database across multiple name servers that can query each other to lookup and cache hostname to IP mappings, using both UDP and TCP protocols to handle queries and full database replication respectively.
This document provides an overview of managing user accounts in a Microsoft Windows Server 2003 environment. It discusses the purpose of user accounts and the authentication process. It also describes how to create and manage local, roaming, and mandatory user profiles. Various methods for creating and modifying user accounts using tools like Active Directory Users and Computers and command line utilities are presented.
The document discusses DNS (Domain Name System) records. It explains that DNS is a hierarchical naming system that maps hostnames to IP addresses. DNS records are the basic data elements that allow DNS servers to perform this mapping. The document describes several important DNS record types including A records, which map hostnames to IPv4 addresses; AAAA records, which map to IPv6 addresses; CNAME records, which map aliases to hostnames; and MX records, which specify mail servers for a domain. It also briefly mentions SOA, PTR, and SRV records along with sources for further information on DNS records.
FTP uses two TCP connections - a control connection on port 21 for sending commands and a data connection on port 20 for transferring files. The control connection maintains state about the user and session and is used to open and close the data connection for individual file transfers. Common FTP commands are used to login with username and password, list directory contents, and get/put files between hosts.
FTP is a protocol for transferring files between a client and server on a network. It defines a client (user) and server model with separate control and data connections to transfer files reliably and efficiently while shielding users from variations in file storage. The control connection uses commands to manage the session and transfer parameters while the data connection handles the actual transfer of files in one of several modes.
DNS, which stands for domain name system, controls your domain name's website and email settings. When visitors go to your domain name, its DNS settings control which company's server it reaches out to.
This document provides an overview of the Domain Name System (DNS) including:
- The DNS uses a globally distributed database to translate human-friendly domain names to computer-friendly IP addresses.
- It has a hierarchical structure with top-level domains like .com and country codes delegated to different name servers, and subdomains can be further delegated.
- DNS name servers store records about their portion of the name space and resolve queries by either responding with records from their cache or by recursively querying other name servers until the answer is found.
The document introduces the DNS system by explaining its purpose of mapping names to resources for easier lookup than numbers. It describes DNS features like global distribution, loose coherency, scalability, reliability, and dynamic updates. Key concepts are explained such as hierarchical DNS names, domains and delegation of subdomains, authoritative and recursive name servers, resource records including SOA and NS records, and how TTL and zone refresh timers maintain consistency.
The document provides an overview of the Domain Name System (DNS). It discusses how DNS was developed to solve problems with the early HOSTS.TXT file system for mapping names to IP addresses. DNS implements a distributed database hierarchy with name servers, resolvers, and a namespace to translate between hostnames and IP addresses. The document outlines the components of DNS and how the domain name resolution process works by querying multiple name servers in a recursive manner to ultimately return an IP address.
The document provides an overview of the Domain Name System (DNS) and Simple Network Management Protocol (SNMP).
DNS is a hierarchical and distributed database that maps domain names to IP addresses. It allows easy-to-remember names to be used instead of hard-to-remember IP addresses. DNS follows a tree structure with top-level domains at the root and subdomains below. DNS servers resolve names to addresses through queries.
SNMP is a network management protocol that allows monitoring and controlling network devices. It uses a simple request-response mechanism to get/set variables and monitor events. SNMP defines a structure for variables and their values using an object identifier system and text files called MIBs.
The document provides an overview of the Domain Name System (DNS) including its history, components, structure, and resolution process. It describes how the DNS evolved from a centralized hosts file to a globally distributed database with name servers authoritative for zones. The resolution process is explained step-by-step through an example query for www.nominum.com. Caching is also demonstrated through a subsequent query for ftp.nominum.com.
We browse the Internet. We host our applications on a server or a cloud that is hooked up with a nice domain name. That’s all there is to know about DNS, right? This talk is a refresher about how DNS works. How we can use it and how it can affect availability of our applications. How we can use it as a means of configuring our application components. How this old geezer protocol is a resilient, distributed system that is used by every Internet user in the world. How we can use it for things that it wasn’t built for. Come join me on this journey through the innards of the web!
The document discusses name resolution services including NIS, DNS, and how they work together. NIS is a local name service, while DNS is global and hierarchical. It describes the components and configuration of DNS, including root, top-level, and subordinate domains as well as master, slave and caching nameservers. The document then provides an example of the name resolution process between a client, local nameserver, and external domain.
The document provides an overview of the Domain Name System (DNS) by discussing its history, components, and purpose. DNS evolved from a centralized hosts file to a distributed database to map domain names to IP addresses as the internet grew. It has three main components: the name space which defines domain name structure, name servers which store DNS information, and resolvers which query name servers to translate names to addresses. DNS provides a global, scalable, and reliable system through data replication and distribution across multiple name servers to lookup information and translate domain names.
The document provides an overview of the Domain Name System (DNS) including:
- DNS is an internet directory service that maps hostnames to IP addresses through a hierarchical domain name space.
- The top of the DNS naming hierarchy is managed by ICANN and includes over 250 top-level domains like .com, .edu, .gov, and country-specific domains.
- DNS resource records like A, MX, NS, and CNAME contain information mapped to domain names, such as IP addresses, mail servers, name servers, and aliases. This information is stored in DNS databases distributed across name servers.
This document summarizes a presentation about DNS (Domain Name System) for developers. It discusses the basics of how DNS works to map domain names to IP addresses, different DNS record types like A, CNAME, and MX records, DNS zones, security considerations like cache poisoning and DNSSEC, using DNS for failover, load balancing, and CDNs, storing configuration data and doing service discovery in DNS, and some unconventional uses of DNS like tunneling HTTP and IP traffic over DNS. The presentation provides examples and demonstrations of these DNS concepts and techniques.
DNS is a core internet protocol that maps domain names to IP addresses. It allows users to connect to internet resources using easy to remember names instead of hard to remember IP addresses. DNS works by having a distributed database of domain name resources across various name servers that are organized hierarchically. A DNS query starts at the root servers and recursively moves down the hierarchy until it reaches an authoritative name server that can provide the IP address associated with the requested domain name. Caching is used to improve performance so that DNS servers can quickly respond to subsequent queries without having to recursively traverse the hierarchy again.
Install and Understand DNSSEC in Linux Server running BIND 9 with CHROOT JAIL system and Service.
By Utah Networxs
Follow - @fabioandpires
Follow - @utah_networxs
1) The document discusses DNS basics including its hierarchical database structure with root and top level domains (TLDs) at the top, and its main components like authoritative servers, recursive resolvers, and resource records.
2) It explains key DNS concepts like domains, zones, and delegation between zones. Common resource record types and a sample zone file are also described.
3) The document covers potential DNS issues like cache poisoning and vulnerabilities if data is not validated, which DNS Security Extensions (DNSSEC) aims to address through cryptographic signing of resource records.
This document provides an introduction to DNS (Domain Name System) in 3 paragraphs:
It explains that DNS was created to address the problems with using a centralized HOSTS.TXT file to map hostnames to IP addresses as the Internet grew. DNS introduced a distributed and hierarchical namespace that maps domain names to IP addresses through a global network of name servers.
It describes the basic structure and functionality of DNS, including that it is organized in a tree structure with top-level domains at the root, each domain can be delegated to different administrators, and name servers contain parts of the distributed database that maps domain names and resource records like A records (IPv4 addresses) and MX records (mail servers).
The
The document discusses the Domain Name System (DNS), which maps human-readable domain names to IP addresses. DNS uses a hierarchical, domain-based naming scheme stored in a distributed database across multiple name servers. When a domain name is queried, DNS performs a recursive lookup by querying name servers at higher levels until it reaches an authoritative name server that can provide the IP address associated with the domain name. Caching of responses improves performance by avoiding unnecessary lookups.
This document provides an overview of the Domain Name System (DNS) and discusses some of its security and censorship implications. It begins with an introduction to DNS basics like its hierarchical structure and mapping of domain names to IP addresses. It then covers security issues such as DNS spoofing, cache poisoning, and reflection attacks. The document also discusses how DNS is used for censorship through blocking domain name resolutions or injecting false DNS responses. Overall, the document provides a high-level tour of the DNS system and some of the ways it can be exploited or manipulated for malicious purposes.
This document discusses DNS (Domain Name System) and how it relates to censorship. It notes that DNS is commonly targeted by censors because it lacks cryptographic integrity, DNSSEC is not widely implemented, and cached DNS data can persist. It describes how censors can block DNS names by pressuring domain name registrars or Internet service providers to change DNS records, effectively blocking access to certain websites indefinitely.
The document provides an overview of the Domain Name System (DNS) including its history, key components, and configuration. DNS converts domain names to IP addresses and vice versa by using a distributed database with a hierarchical structure. The database is divided into zones stored on nameservers. Resolvers query nameservers to lookup names and return results to requesting programs. The document outlines the DNS namespace, nameservers, zones, resource records, configuration files, and utilities for testing and querying DNS.
KuberTENes Birthday Bash Guadalajara - K8sGPT first impressionsVictor Morales
K8sGPT is a tool that analyzes and diagnoses Kubernetes clusters. This presentation was used to share the requirements and dependencies to deploy K8sGPT in a local environment.
Optimizing Gradle Builds - Gradle DPE Tour Berlin 2024Sinan KOZAK
Sinan from the Delivery Hero mobile infrastructure engineering team shares a deep dive into performance acceleration with Gradle build cache optimizations. Sinan shares their journey into solving complex build-cache problems that affect Gradle builds. By understanding the challenges and solutions found in our journey, we aim to demonstrate the possibilities for faster builds. The case study reveals how overlapping outputs and cache misconfigurations led to significant increases in build times, especially as the project scaled up with numerous modules using Paparazzi tests. The journey from diagnosing to defeating cache issues offers invaluable lessons on maintaining cache integrity without sacrificing functionality.
A review on techniques and modelling methodologies used for checking electrom...nooriasukmaningtyas
The proper function of the integrated circuit (IC) in an inhibiting electromagnetic environment has always been a serious concern throughout the decades of revolution in the world of electronics, from disjunct devices to today’s integrated circuit technology, where billions of transistors are combined on a single chip. The automotive industry and smart vehicles in particular, are confronting design issues such as being prone to electromagnetic interference (EMI). Electronic control devices calculate incorrect outputs because of EMI and sensors give misleading values which can prove fatal in case of automotives. In this paper, the authors have non exhaustively tried to review research work concerned with the investigation of EMI in ICs and prediction of this EMI using various modelling methodologies and measurement setups.
DEEP LEARNING FOR SMART GRID INTRUSION DETECTION: A HYBRID CNN-LSTM-BASED MODELgerogepatton
As digital technology becomes more deeply embedded in power systems, protecting the communication
networks of Smart Grids (SG) has emerged as a critical concern. Distributed Network Protocol 3 (DNP3)
represents a multi-tiered application layer protocol extensively utilized in Supervisory Control and Data
Acquisition (SCADA)-based smart grids to facilitate real-time data gathering and control functionalities.
Robust Intrusion Detection Systems (IDS) are necessary for early threat detection and mitigation because
of the interconnection of these networks, which makes them vulnerable to a variety of cyberattacks. To
solve this issue, this paper develops a hybrid Deep Learning (DL) model specifically designed for intrusion
detection in smart grids. The proposed approach is a combination of the Convolutional Neural Network
(CNN) and the Long-Short-Term Memory algorithms (LSTM). We employed a recent intrusion detection
dataset (DNP3), which focuses on unauthorized commands and Denial of Service (DoS) cyberattacks, to
train and test our model. The results of our experiments show that our CNN-LSTM method is much better
at finding smart grid intrusions than other deep learning algorithms used for classification. In addition,
our proposed approach improves accuracy, precision, recall, and F1 score, achieving a high detection
accuracy rate of 99.50%.
International Conference on NLP, Artificial Intelligence, Machine Learning an...gerogepatton
International Conference on NLP, Artificial Intelligence, Machine Learning and Applications (NLAIM 2024) offers a premier global platform for exchanging insights and findings in the theory, methodology, and applications of NLP, Artificial Intelligence, Machine Learning, and their applications. The conference seeks substantial contributions across all key domains of NLP, Artificial Intelligence, Machine Learning, and their practical applications, aiming to foster both theoretical advancements and real-world implementations. With a focus on facilitating collaboration between researchers and practitioners from academia and industry, the conference serves as a nexus for sharing the latest developments in the field.
Introduction- e - waste – definition - sources of e-waste– hazardous substances in e-waste - effects of e-waste on environment and human health- need for e-waste management– e-waste handling rules - waste minimization techniques for managing e-waste – recycling of e-waste - disposal treatment methods of e- waste – mechanism of extraction of precious metal from leaching solution-global Scenario of E-waste – E-waste in India- case studies.
Comparative analysis between traditional aquaponics and reconstructed aquapon...bijceesjournal
The aquaponic system of planting is a method that does not require soil usage. It is a method that only needs water, fish, lava rocks (a substitute for soil), and plants. Aquaponic systems are sustainable and environmentally friendly. Its use not only helps to plant in small spaces but also helps reduce artificial chemical use and minimizes excess water use, as aquaponics consumes 90% less water than soil-based gardening. The study applied a descriptive and experimental design to assess and compare conventional and reconstructed aquaponic methods for reproducing tomatoes. The researchers created an observation checklist to determine the significant factors of the study. The study aims to determine the significant difference between traditional aquaponics and reconstructed aquaponics systems propagating tomatoes in terms of height, weight, girth, and number of fruits. The reconstructed aquaponics system’s higher growth yield results in a much more nourished crop than the traditional aquaponics system. It is superior in its number of fruits, height, weight, and girth measurement. Moreover, the reconstructed aquaponics system is proven to eliminate all the hindrances present in the traditional aquaponics system, which are overcrowding of fish, algae growth, pest problems, contaminated water, and dead fish.
Using recycled concrete aggregates (RCA) for pavements is crucial to achieving sustainability. Implementing RCA for new pavement can minimize carbon footprint, conserve natural resources, reduce harmful emissions, and lower life cycle costs. Compared to natural aggregate (NA), RCA pavement has fewer comprehensive studies and sustainability assessments.
Embedded machine learning-based road conditions and driving behavior monitoringIJECEIAES
Car accident rates have increased in recent years, resulting in losses in human lives, properties, and other financial costs. An embedded machine learning-based system is developed to address this critical issue. The system can monitor road conditions, detect driving patterns, and identify aggressive driving behaviors. The system is based on neural networks trained on a comprehensive dataset of driving events, driving styles, and road conditions. The system effectively detects potential risks and helps mitigate the frequency and impact of accidents. The primary goal is to ensure the safety of drivers and vehicles. Collecting data involved gathering information on three key road events: normal street and normal drive, speed bumps, circular yellow speed bumps, and three aggressive driving actions: sudden start, sudden stop, and sudden entry. The gathered data is processed and analyzed using a machine learning system designed for limited power and memory devices. The developed system resulted in 91.9% accuracy, 93.6% precision, and 92% recall. The achieved inference time on an Arduino Nano 33 BLE Sense with a 32-bit CPU running at 64 MHz is 34 ms and requires 2.6 kB peak RAM and 139.9 kB program flash memory, making it suitable for resource-constrained embedded systems.
Presentation of IEEE Slovenia CIS (Computational Intelligence Society) Chapte...University of Maribor
Slides from talk presenting:
Aleš Zamuda: Presentation of IEEE Slovenia CIS (Computational Intelligence Society) Chapter and Networking.
Presentation at IcETRAN 2024 session:
"Inter-Society Networking Panel GRSS/MTT-S/CIS
Panel Session: Promoting Connection and Cooperation"
IEEE Slovenia GRSS
IEEE Serbia and Montenegro MTT-S
IEEE Slovenia CIS
11TH INTERNATIONAL CONFERENCE ON ELECTRICAL, ELECTRONIC AND COMPUTING ENGINEERING
3-6 June 2024, Niš, Serbia
ACEP Magazine edition 4th launched on 05.06.2024Rahul
This document provides information about the third edition of the magazine "Sthapatya" published by the Association of Civil Engineers (Practicing) Aurangabad. It includes messages from current and past presidents of ACEP, memories and photos from past ACEP events, information on life time achievement awards given by ACEP, and a technical article on concrete maintenance, repairs and strengthening. The document highlights activities of ACEP and provides a technical educational article for members.
A SYSTEMATIC RISK ASSESSMENT APPROACH FOR SECURING THE SMART IRRIGATION SYSTEMSIJNSA Journal
The smart irrigation system represents an innovative approach to optimize water usage in agricultural and landscaping practices. The integration of cutting-edge technologies, including sensors, actuators, and data analysis, empowers this system to provide accurate monitoring and control of irrigation processes by leveraging real-time environmental conditions. The main objective of a smart irrigation system is to optimize water efficiency, minimize expenses, and foster the adoption of sustainable water management methods. This paper conducts a systematic risk assessment by exploring the key components/assets and their functionalities in the smart irrigation system. The crucial role of sensors in gathering data on soil moisture, weather patterns, and plant well-being is emphasized in this system. These sensors enable intelligent decision-making in irrigation scheduling and water distribution, leading to enhanced water efficiency and sustainable water management practices. Actuators enable automated control of irrigation devices, ensuring precise and targeted water delivery to plants. Additionally, the paper addresses the potential threat and vulnerabilities associated with smart irrigation systems. It discusses limitations of the system, such as power constraints and computational capabilities, and calculates the potential security risks. The paper suggests possible risk treatment methods for effective secure system operation. In conclusion, the paper emphasizes the significant benefits of implementing smart irrigation systems, including improved water conservation, increased crop yield, and reduced environmental impact. Additionally, based on the security analysis conducted, the paper recommends the implementation of countermeasures and security approaches to address vulnerabilities and ensure the integrity and reliability of the system. By incorporating these measures, smart irrigation technology can revolutionize water management practices in agriculture, promoting sustainability, resource efficiency, and safeguarding against potential security threats.
Using recycled concrete aggregates (RCA) for pavements is crucial to achieving sustainability. Implementing RCA for new pavement can minimize carbon footprint, conserve natural resources, reduce harmful emissions, and lower life cycle costs. Compared to natural aggregate (NA), RCA pavement has fewer comprehensive studies and sustainability assessments.
Recycled Concrete Aggregate in Construction Part II
Domain Name System(ppt)
1. DNS
( DOMAIN NAME SYSTEM )
Prepared by:
•YASH NIMAVAT-91600103106
•BHAUTIK CHOVATIYA-91600103130
•CHETAN KHUNTI-91600103105
•BHAVIK VAISHNANI-91600103074
•JAY JOSHI-91600103094
2. Overview
Introduction to the DNS
DNS Components
The name space
The servers
The resolvers
DNS Structure and Hierarchy
The DNS in Context
3. DNS History
ARPANET utilized a central file HOSTS.TXT
Contains names to addresses mapping
Maintained by SRI’s NIC (Stanford-Research-Institute:
Network-Information-Center)
Administrators email changes to NIC
NIC updates HOSTS.TXT periodically
Administrators FTP (download) HOSTS.TXT
4. As the system grew, HOSTS.TXT had problems
with:
Scalability (traffic and load)
Name collisions
Consistency
In 1984, Paul Mockapetris released the first
version (RFCs* 882 and 883, superseded by 1034
and 1035 …)
*RFC: Request for Comments
5. The DNS is…
The “Domain Name System”.
What Internet users use to reference anything by
name on the Internet.
The mechanism by which Internet software
translates names to attributes such as addresses.
6. The DNS is also…
A globally distributed, scalable, reliable database.
Comprised of three components :
A “name space”
Servers making that name space available
Resolvers (clients) which query the servers about the name
space
7. DNS as a Lookup Mechanism
Users generally prefer names to numbers
e.g. – google.com, fb.com etc.
Computers prefer numbers to names
e.g. – 10.2.1.32, 10.2.4.56 etc.
DNS provides the mapping between the two
I have “x”, give me “y”
i.e. for e.g. : “google.com” with “10.2.1.32”.
8. DNS as a Database
Keys to the database are “domain names”
www.foo.com, 18.in-addr.arpa, 6.4.e164.arpa
Over 200,000,000 domain names stored.
Each domain name contains one or more attributes:
Known as “resource records”
Each attribute individually retrievable.
9. Global Distribution
Data is maintained locally, but retrievable globally
No single computer has all DNS data
DNS lookups can be performed by any device.
Remote DNS data is locally cacheable to improve
performance.
10. Loose Coherency
Each version of a subset of the database (a zone)
has a serial number
The serial number is incremented on each database change
Changes to the master copy of the database are
propagated to replicas according to timing set by
the zone administrator
Cached data expires according to timeout set by
zone administrator
11. Scalability
No limit to the size of the database.
No limit to the number of queries
Tens of thousands of queries handled easily every second
Queries distributed among masters, slaves, and
caches.
12. Reliability
Data is replicated
Data from master is copied to multiple slaves
Clients can query
Master server
Any of the copies at slave servers
Clients will typically query local caches.
DNS protocols can use either UDP or TCP
If UDP, DNS protocol handles retransmission,
sequencing, etc.
13. Dynamicity
Database can be updated dynamically
Add/delete/modify of any record
Only master can be dynamically updated
Modification of the master database triggers
replication.
14. The Name Space
The name space is the structure of the DNS
database
An inverted tree with the root node at the top.
Each node has a label
The root node has a null label, written as “”
t h ir d -le v e l n o d e
s e c o n d - le v e l n o d e s e c o n d - le v e l n o d e
t o p -le v e l n o d e
t h ir d -le v e l n o d e t h ir d -le v e l n o d e
s e c o n d - le v e l n o d e
t o p -le v e l n o d e
s e c o n d - le v e l n o d e s e c o n d - le v e l n o d e
t o p -le v e l n o d e
T h e r o o t n o d e
" "
16. fo o fo o
to p -1
fo o a t& t
to p -2
b a r b a z
to p -3
""
Labels
Each node in the tree
must have a label
A string of up to 63 bytes
RFCs 852 and 1123 define
legal characters for
“hostnames”
A-Z, 0-9, and “-” only with
a-z and A-Z treated as the
same.
Sibling nodes must
have unique labels.
The null label is
reserved for the root
node.
17. Domain Names
A domain name is the sequence of labels from a node
to the root, separated by dots (“.”s), read left to right
The name space has a maximum depth of 127 levels
Domain names are limited to 255 characters in length
A node’s domain name identifies its position in the
name space
d a k o ta
w e s t
t o r n a d o
e a s t w w w
n o m in u m m e ta in fo
c o m
b e r k e le y n w u
e d u g o v
n a to
in t
a r m y
m il
u u
n e t o rg
" "
18. Subdomains
One domain is a subdomain of another if its domain
name ends in the other’s domain name
So sales.nominum.com is a subdomain of
nominum.com & .com
nominum.com is a subdomain of .com
19. Dividing a Domain into Zones
.a r p a
a c m e b w
m o lo k a i s k y e
r w c w w w f tp
g o u d a c h e d d a r
a m s
n o m in u m n e ts o l
.c o m . e d u
" "
nominum.com
domain
nominum.com
zone
ams.nominum.com
zonerwc.nominum.com
zone
20. Name Servers
Name servers store information about the name
space in units called “zones”
The name servers that load a complete zone are said to
“have authority for” or “be authoritative for” the zone
Usually, more than one name server are
authoritative for the same zone
This ensures redundancy and spreads the load
21. Name Servers and Zones
128.8.10.5
nominum.com
204.152.187.11
202.12.28.129
Name Servers
isc.org
Zones128.8.10.5 serves
data for both
nominum.com
and isc.org zones
202.12.28.129
serves data for
nominum.com
zone only
204.152.187.11
serves data for
isc.org zone only
22. Types of Name Servers
Two main types of servers
Authoritative – maintains the data
Master – where the data is edited
Slave – where data is replicated to
Caching – stores data obtained from an authoritative server
No special hardware necessary.
23. Name Server Architecture
You can think of a name server as part of:
database server, answering queries about the parts of the
name space it knows about (i.e., is authoritative for),
cache, temporarily storing data it learns from other name
servers, and
agent, helping resolvers and other name servers find data
24. Name Resolution
Name resolution is the process by which
resolvers and name servers cooperate to find
data in the name space
Closure mechanism for DNS?
Starting point: the names and IP addresses of the name
servers for the root zone (the “root name servers”)
The root name servers know about the top-level zones
and can tell name servers whom to contact for all
TLD(TOP LEVEL DOMAINS).
25. Name Resolution
A DNS query has three parameters:
A domain name (e.g., www.nominum.com),
Remember, every node has a domain name!
A class (e.g., IN), and
A type (e.g., A)
http://network-tools.com/nslook/
Upon receiving a query from a resolver, a
name server :
1) looks for the answer in its authoritative data and its
cache.
2) If step 1 fails, the answer must be looked up
27. What’s the IP address
of
www.nominum.com?
The workstation annie asks its configured
name server, dakota, for
www.nominum.com’s address
ping www.nominum.com.
annie.west.sprockets.com
dakota.west.sprockets.com
28. The name server dakota asks a root name server, m,
for www.nominum.com’s address
ping www.nominum.com.
annie.west.sprockets.com
m.root-servers.net
dakota.west.sprockets.com
What’s the IP address
of
www.nominum.com?
29. The root server m refers dakota to the com name
servers
This type of response is called a “referral”
ping www.nominum.com.
annie.west.sprockets.com
m.root-servers.net
dakota.west.sprockets.com Here’s a list of the
com name servers.
Ask one of them.
30. The name server dakota asks a com name
server, f, for www.nominum.com’s address
ping www.nominum.com.
annie.west.sprockets.com
m.root-servers.net
dakota.west.sprockets.com
What’s the IP address
of
www.nominum.com?
f.gtld-servers.net
31. The com name server f refers dakota to the
nominum.com name servers
ping www.nominum.com.
annie.west.sprockets.com
f.gtld-servers.net
m.root-servers.net
dakota.west.sprockets.com
Here’s a list of the
nominum.com
name servers.
Ask one of them.
32. The name server dakota asks a nominum.com name
server, ns1.sanjose, for www.nominum.com’s address
ping www.nominum.com.
annie.west.sprockets.com
f.gtld-servers.net
m.root-servers.net
dakota.west.sprockets.com
ns1.sanjose.nominum.net
What’s the IP address
of
www.nominum.com?
33. The nominum.com name server ns1.sanjose
responds with www.nominum.com’s address
ping www.nominum.com.
annie.west.sprockets.com
f.gtld-servers.net
m.root-servers.net
dakota.west.sprockets.com
ns1.sanjose.nominum.netHere’s the IP
address for
www.nominum.com
34. Here’s the IP
address for
www.nominum.com
The name server dakota responds to annie
with www.nominum.com’s address
ping www.nominum.com.
annie.west.sprockets.com
f.gtld-servers.net
m.root-servers.net
dakota.west.sprockets.com
ns1.sanjose.nominum.net
35. ping ftp.nominum.com.
Resolution Process (Caching)
After the previous query, the name server dakota now
knows:
The names and IP addresses of the com name servers
The names and IP addresses of the nominum.com name
servers
The IP address of www.nominum.com
Let’s look at the resolution process again
annie.west.sprockets.com
36. ping ftp.nominum.com.
What’s the IP address
of ftp.nominum.com?
The workstation annie asks its configured
name server, dakota, for ftp.nominum.com’s
address
annie.west.sprockets.com
f.gtld-servers.net
m.root-servers.net
dakota.west.sprockets.com
ns1.sanjose.nominum.net
37. ping ftp.nominum.com.
What’s the IP address
of ftp.nominum.com?
Resolution Process (Caching)
dakota has cached a NS record indicating ns1.sanjose
is an nominum.com name server, so it asks it for
ftp.nominum.com’s address
annie.west.sprockets.com
f.gtld-servers.net
m.root-servers.net
dakota.west.sprockets.com
ns1.sanjose.nominum.net
38. ping ftp.nominum.com.
Here’s the IP
address for
ftp.nominum.com
The nominum.com name server ns1.sanjose
responds with ftp.nominum.com’s address
annie.west.sprockets.com
f.gtld-servers.net
m.root-servers.net
dakota.west.sprockets.com
ns1.sanjose.nominum.net
39. ping ftp.nominum.com.
Here’s the IP
address for
ftp.nominum.com
The name server dakota responds to annie
with ftp.nominum.com’s address
annie.west.sprockets.com
f.gtld-servers.net
m.root-servers.net
dakota.west.sprockets.com
ns1.sanjose.nominum.net
40. DNS Structure and Hierarchy
The DNS imposes no constraints on how the DNS
hierarchy is implemented except:
A single root
The label restrictions
So, can we create a host with a name
a.wonderful.world?
If a site is not connected to the Internet, it can use
any domain hierarchy it chooses
Can make up whatever TLDs (top level domains) you
want
Connecting to the Internet implies use of the
existing DNS hierarchy
41. Top-level Domain (TLD) Structure
In 1983 (RFC 881), the idea was to have TLDs
correspond to network service providers
e.g., ARPA, DDN, CSNET, etc.
By 1984 (RFC 920), functional domains was
established
e.g., GOV for Government, COM for commercial,
EDU for education, etc.
RFC 920 also
Provided country domains
Provided “Multiorganizations”
42. The Current TLDs
C O M
C o m m e r c ia l O r g a n iz a tio n s
N E T
N e tw o rk I n fr a s tr u c tu re
O R G
O t h e r O r g a n iz a tio n s
G e n e r ic T L D s
( g T L D s )
A F
A fg h a n is t a n
A L
A lb a n ia
D Z
A lg e r ia
. ..
Y U
Y u g o s la v ia
Z M
Z a m b ia
Z W
Z im b a b w e
C o u n try C o d e T L D s
( c c T L D s )
I N T
I n t e r n a t io n a l T r e a ty O r g a n iz a t io n s
A R P A
( T r a n s itio n D e v ic e )
In t e rn a t io n a l T L D s
( iT L D s )
G O V
G o v e r n m e n t a l O r g a n iz a tio n s
M I L
M ilit a r y O r g a n iz a t io n s
E D U
E d u c a t io n a l I n s t it u tio n s
U S L e g a c y T L D s
( u s T L D s )
" ."
43. Root Name Server Operators
Nameserver Operated by:
A Verisign (US East Coast)
B University of S. California –Information Sciences Institute (US West Coast)
C Cogent Communications (US East Coast)
D University of Maryland (US East Coast)
E NASA (Ames) (US West Coast)
F Internet Software Consortium (US West Coast)
G U. S. Dept. of Defense (ARL) (US East Coast)
H U. S. Dept. of Defense (DISA) (US East Coast)
I Autonomica (SE)
J Verisign (US East Coast)
K RIPE-NCC (UK)
L ICANN (US West Coast)
M WIDE (JP)
44. The Root Nameservers
The root zone file lists the names and IP addresses
of the authoritative DNS servers for all top-level
domains (TLDs)
The root zone file is published on 13 servers, “A”
through “M”, around the Internet
Root name server operations currently provided by
volunteer efforts by a very diverse set of
organizations
45. Registries, Registrars, and Registrants
A classification of roles in the operation of a domain
name space
Registry
the name space’s database
the organization which has edit control of that database
Registrar
the agent which submits change requests to the registry on
behalf of the registrant
46. Registrant
the entity which makes use of the domain name
.COM, .NET, and .ORG
By far the largest top level domains on the Internet today
Verisign received the contract for the registry
for .COM, .NET, and .ORG
also a registrar for these TLDs
47. Registries, Registrars, and Registrants
Registry Zone DB
RegistrantsRegistrants
End user requests
add/modify/delete
Registrar submits
add/modify/delete
to registry
Registrar RegistrarRegistrar
Master
updated
Registry updates
zone
Slaves
updated
48. Load Concerns
DNS can handle the load
DNS root servers get approximately 3000 queries per second
Empirical proofs (DDoS attacks) show root name servers can
handle 50,000 queries per second
Limitation is network bandwidth, not the DNS protocol
in-addr.arpa zone, which translates numbers to names, gets
about 2000 queries per second
49.
50. Performance Concerns
DNS is a very lightweight protocol
Simple query – response
Any performance limitations are the result of
network limitations
Speed of light
Network congestion
Switching/forwarding latencies
51. Security Concerns
Base DNS protocol (RFC 1034, 1035) is insecure
DNS spoofing (cache poisoning) attacks are possible
DNS Security Enhancements (DNSSEC, RFC
2565) remedies this flaw
But creates new ones
DoS attacks
Amplification attacks
Advanced Research Projects Agency Network (ARPANET) was the world's first operational packet switching network, the first network to implement TCP/IP
ITU: International Telecommunication Union
1: US/CA
81: JP
BIND: Berkeley Internet Name Domain
Also, the caching resolver can insert data into the cache, and can "query" the cache and the database server.
ARPA: Advanced Research Projects Agency
ARPA: originally was the acronym for the Advanced Research Projects Agency (ARPA), the funding organization in the United States that developed the precursor of the Internet (ARPANET),
it now stands for Address and Routing Parameter Area.
a spoofing attack is a situation in which one person or program successfully masquerades as another by falsifying data