Upstream server

Last updated

In computer networking, upstream server refers to a server that provides service to another server. In other words, upstream server is a server that is located higher in a hierarchy of servers. The highest server in the hierarchy is sometimes called the origin server. The inverse term, downstream server, is rarely used.

The terms are exclusively used in contexts where requests and responses move in opposite ways. It is not used when discussing hierarchical routing or hierarchical network topologies, as packets can be transferred both ways.

For example, in the domain name system, a name server in a company's local area network often forwards requests to the internet service provider's (ISP's) name servers, instead of resolving the domain name directly it can be said that the ISP's name servers are upstream to the local server. Conversely, the ISP's servers typically resolve domain names from the domain's authoritative origin servers the authoritative servers are said to be upstream to the ISP's servers. Note that the hierarchy of resolvers is unrelated to the actual domain name hierarchy.


Related Research Articles

The Domain Name System (DNS) is a hierarchical and decentralized naming system for computers, services, or other resources 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 locating and identifying computer services and devices with the underlying network protocols. By providing a worldwide, distributed directory service, the Domain Name System has been an essential component of the functionality of the Internet since 1985.

The Dynamic Host Configuration Protocol (DHCP) is a network management protocol used on Internet Protocol (IP) networks for automatically assigning IP addresses and other communication parameters to devices connected to the network using a client–server architecture.

A name server refers to the server component of the Domain Name System (DNS), one of the two principal namespaces of the Internet. The most important function of DNS servers is the translation (resolution) of human-memorable domain names (example.com) and hostnames into the corresponding numeric Internet Protocol (IP) addresses (93.184.216.34), the second principal name space of the Internet which is used to identify and locate computer systems and resources on the Internet.

Proxy server Computer server that makes and receives requests on behalf of a user

In computer networking, a proxy server is a server application that acts as an intermediary between a client requesting a resource and the server providing that resource.

Root name server Name server for the DNS root zone

A root name server is a name server for the root zone of the Domain Name System (DNS) of the Internet. It directly answers requests for records in the root zone and answers other requests by returning a list of the authoritative name servers for the appropriate top-level domain (TLD). The root name servers are a critical part of the Internet infrastructure because they are the first step in translating (resolving) human readable host names into IP addresses that are used in communication between Internet hosts.

The Domain Name System Security Extensions (DNSSEC) is a suite of extension specifications by the Internet Engineering Task Force (IETF) for securing data exchanged in the Domain Name System (DNS) in Internet Protocol (IP) networks. The protocol provides cryptographic authentication of data, authenticated denial of existence, and data integrity, but not availability or confidentiality.

The Internet uses the Domain Name System (DNS) to associate numeric computer IP addresses with human-readable names. The top level of the domain name hierarchy, the DNS root, contains the top-level domains that appear as the suffixes of all Internet domain names. The most widely used DNS root is administered by the Internet Corporation for Assigned Names and Numbers (ICANN). In addition, several organizations operate alternative DNS roots, often referred to as alt roots. These alternative domain name systems operate their own root name servers and commonly administer their own specific name spaces consisting of custom top-level domains.

In computer networking, localhost is a hostname that refers to the current computer used to access it. It is used to access the network services that are running on the host via the loopback network interface. Using the loopback interface bypasses any local network interface hardware.

In the Domain Name System (DNS) hierarchy, a subdomain is a domain that is a part of another (main) domain. For example, if a domain offered an online store as part of their website example.com, it might use the subdomain shop.example.com.

A DNS zone is any distinct, contiguous portion of the domain name space in the Domain Name System (DNS) for which administrative responsibility has been delegated to a single manager.

DNS spoofing, also referred to as DNS cache poisoning, is a form of computer security hacking in which corrupt Domain Name System data is introduced into the DNS resolver's cache, causing the name server to return an incorrect result record, e.g. an IP address. This results in traffic being diverted to the attacker's computer.

Pharming is a cyberattack intended to redirect a website's traffic to another, fake site. Pharming can be conducted either by changing the hosts file on a victim's computer or by exploitation of a vulnerability in DNS server software. DNS servers are computers responsible for resolving Internet names into their real IP addresses. Compromised DNS servers are sometimes referred to as "poisoned". Pharming requires unprotected access to target a computer, such as altering a customer's home computer, rather than a corporate business server.

Bandwidth throttling is the intentional slowing or speeding of an internet service by an Internet service provider (ISP). It is a reactive measure employed in communication networks to regulate network traffic and minimize bandwidth congestion. Bandwidth throttling can occur at different locations on the network. On a local area network (LAN), a system administrator ("sysadmin") may employ bandwidth throttling to help limit network congestion and server crashes. On a broader level, the Internet service provider may use bandwidth throttling to help reduce a user's usage of bandwidth that is supplied to the local network. Bandwidth throttling is also used as a measurement of data rate on Internet speed test websites.

This article presents a comparison of the features, platform support, and packaging of many independent implementations of Domain Name System (DNS) name server software.

OpenDNS Domain name system provided by Cisco using closed-source software

OpenDNS is an American company providing Domain Name System (DNS) resolution services—with features such as phishing protection, optional content filtering, and DNS lookup in its DNS servers—and a cloud computing security product suite, Umbrella, designed to protect enterprise customers from malware, botnets, phishing, and targeted online attacks. The OpenDNS Global Network processes an estimated 100 billion DNS queries daily from 85 million users through 25 data centers worldwide.

DNS hijacking, DNS poisoning, or DNS redirection is the practice of subverting the resolution of Domain Name System (DNS) queries. This can be achieved by malware that overrides a computer's TCP/IP configuration to point at a rogue DNS server under the control of an attacker, or through modifying the behaviour of a trusted DNS server so that it does not comply with internet standards.

Usenet Worldwide distributed Internet discussion system

Usenet is a worldwide distributed discussion system available on computers. It was developed from the general-purpose Unix-to-Unix Copy (UUCP) dial-up network architecture. Tom Truscott and Jim Ellis conceived the idea in 1979, and it was established in 1980. Users read and post messages to one or more categories, known as newsgroups. Usenet resembles a bulletin board system (BBS) in many respects and is the precursor to Internet forums that became widely used. Discussions are threaded, as with web forums and BBSs, though posts are stored on the server sequentially.

A DNS leak refers to a security flaw that allows DNS requests to be revealed to ISP DNS servers, despite the use of a VPN service to attempt to conceal them. Although primarily of concern to VPN users, it is also possible to prevent it for proxy and direct internet users.

DNS over TLS (DoT) is a network security protocol for encrypting and wrapping Domain Name System (DNS) queries and answers via the Transport Layer Security (TLS) protocol. The goal of the method is to increase user privacy and security by preventing eavesdropping and manipulation of DNS data via man-in-the-middle attacks.

1.1.1.1 is a free Domain Name System (DNS) service by American company Cloudflare in partnership with APNIC. The service functions as a recursive name server providing domain name resolution for any host on the Internet. The service was announced on April 1, 2018. On November 11, 2018, Cloudflare announced a mobile application of their 1.1.1.1 service for Android and iOS. On September 25, 2019, Cloudflare released WARP, an upgraded version of their original 1.1.1.1 mobile application.