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WO2009005433A1 - Gestionnaire de dns - Google Patents

Gestionnaire de dns Download PDF

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Publication number
WO2009005433A1
WO2009005433A1 PCT/SE2007/050504 SE2007050504W WO2009005433A1 WO 2009005433 A1 WO2009005433 A1 WO 2009005433A1 SE 2007050504 W SE2007050504 W SE 2007050504W WO 2009005433 A1 WO2009005433 A1 WO 2009005433A1
Authority
WO
WIPO (PCT)
Prior art keywords
dns
configuration file
address
manager
resolver
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/SE2007/050504
Other languages
English (en)
Inventor
Tero Aleksanteri Kauppinen
Martti Kuparinen
Heikki Mahkonen
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Telefonaktiebolaget LM Ericsson AB
Original Assignee
Telefonaktiebolaget LM Ericsson AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Telefonaktiebolaget LM Ericsson AB filed Critical Telefonaktiebolaget LM Ericsson AB
Priority to PCT/SE2007/050504 priority Critical patent/WO2009005433A1/fr
Publication of WO2009005433A1 publication Critical patent/WO2009005433A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L61/00—Network arrangements, protocols or services for addressing or naming
    • H04L61/45—Network directories; Name-to-address mapping
    • H04L61/4505—Network directories; Name-to-address mapping using standardised directories; using standardised directory access protocols
    • H04L61/4511—Network directories; Name-to-address mapping using standardised directories; using standardised directory access protocols using domain name system [DNS]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L61/00—Network arrangements, protocols or services for addressing or naming
    • H04L61/50—Address allocation
    • H04L61/5007—Internet protocol [IP] addresses
    • H04L61/5014—Internet protocol [IP] addresses using dynamic host configuration protocol [DHCP] or bootstrap protocol [BOOTP]

Definitions

  • the present invention relates to a host computer system designed for communicating with a plurality of Domain Name System, (DNS) servers.
  • DNS Domain Name System
  • IP addresses are cumbersome to use and difficult to remember. It is easier to use and to remember a host name (such as www.company.com) than the corresponding IP address.
  • a DNS server has a database that translates the user friendly host names into numeric IP addresses. When the user for example wants to access a home page on the web, he types the host name in a field in the web browser. This host name is sent from the web browser (the user client) via the operating system to the DNS server. In order to find the DNS server, the IP address to the DNS server itself must have been defined beforehand, either manually by the user or automatically e.g.
  • the IP address to the DNS server is stored in a resolver configuration file. In a Unix/Linux operating system this corresponds to the ⁇ etc/resolv. conf file whole other operating systems may use other names.
  • the DNS server receives the host name it makes a look-up in a database and returns the IP address associated with the provided host name. The received IP address is then used to route IP packets to the application server that is hosting the home page the user is interested in. This translation process (also called address resolution) is almost instant and is completed without the user ever notices any delay.
  • the resolver caches the information it receives when it resolves queries. These cached responses can then be used to answer subsequent queries for the same information.
  • the cached data has a limited lifetime specified in the Time to Live (TTL) parameter returned with the data.
  • TTL Time to Live
  • DNS Domain Name System
  • DHCP Dynamic Host Configuration Protocol
  • IPv6 IP version 6
  • Another problem is that in a situation where one DNS server actually can be reached over say two network interfaces and where one interface goes down or becomes unavailable, address resolution requests intended to be sent over the unavailable interface can not reach the DNS server even if there is a second available interface over which the DNS still can be reached.
  • the DNS manager analyzes an address resolution request originating from one of the user clients and to pass this request to one of the DNS servers over one of said network interfaces.
  • the invention further comprises a first resolver configuration file that is arranged to store the address to the DNS manager and a second resolver configuration file arranged to store the addresses to the plurality of DNS servers and the identities of the network interfaces.
  • An advantage with the current invention is that a multitude of address resolution requests can be performed simultaneously and without interfering with each other.
  • Another advantage is that if one network interface fails (or becomes unavailable due to the host is moving) , it is possible to access a DNS server through another network interface .
  • the objective with the current invention is therefore to enable a multi-interface host to simultaneously access different networks having different DNS servers without the resolution requests are interfering with each other.
  • Figure 1 is a block diagram showing a known host computer system (such as a PC) connected to a DNS server.
  • Figure 2 is a block diagram showing a first embodiment of the current invention.
  • Figure 3 is a block diagram showing a second embodiment of the current invention.
  • Figure 4 is a flow chart illustrating the method to perform address resolution according to the current invention.
  • Figure 5 is a flow chart illustrating the method of updating the first and second resolver configuration files in the current invention.
  • FIG. 1 A commonly known host computer system (such as a PC) , is illustrated in Figure 1.
  • This computer system 110 is designed to access a DNS server 120, a DHCP server 130 and an application server 140.
  • the computer system 110 comprises for example two user clients where in Figure 1 one is a web browser client 111 and the other is a mail client 112.
  • the computer system 110 does also comprise an address resolver
  • the resolver 113 is a set of software routines that provide access to the DNS server 120.
  • the computer system 110 does also comprise a first resolver configuration file 114.
  • This file 114 in a Unix/Linux operating system corresponds to the /etc/resolv. conf file located in the /etc directory. Other operating systems may have other names.
  • the resolver configuration file 114 contains configuration settings that are read by the resolver such as the IP address of the DNS server that can translate received host names into IP addresses for a node in the network.
  • the computer system 110 further comprises a DHCP (Dynamic Host Configuration Protocol) client 115 which is designed to communicate with the DHCP server 130 using the DHCP protocol.
  • the DHCP server 130 has a pool of available IP addresses in a database.
  • the DHCP server 130 distributes these IP addresses and other configuration settings (like subnet masks etc) to the DHCP client 115.
  • the DHCP client 115 sends a BOOTP (Bootstrap Protocol) request to the DHCP server 130 which offers an IP address from the pool of IP addresses. This IP address is then used as the IP address to the mail- or web browser client 111,112.
  • the DHCP server 130 is also designed to automatically inform the DHCP client 115 in the computer system 110 about the IP address to the DNS server 120. This IP address is stored in the resolver configuration file 114.
  • the DHCP client 115 is also designed to update the resolver configuration file 114 when any IP addresses and/or other configuration settings change .
  • Figure 2 illustrates a host computer system 210 according to the current invention having a plurality of network interfaces 231-233.
  • the resolver 113 and the first resolver configuration file 114 known from Figure 1 two new entities have been introduced, a DNS manager 216 and a second resolver configuration file 217.
  • At least one modified DHCP client 215 has also been introduced.
  • Each modified DHCP client 215 is run for each network interface 231-233.
  • one DHCP client 215 can be run for every network interface 231- 233.
  • the DNS manager 216 is designed to handle resolution requests from a plurality of the user clients 111,112 towards a plurality of DNS servers 221-223 over the plurality of network interfaces 231-233. Each DNS server 221-223 may belong to different networks 241-243 respectively.
  • the DNS manager 216 is also designed to read and write the content in the first resolver configuration file 114 and in the second resolver configuration file 217.
  • the modified DHCP client 215 is designed to communicate with the DHCP server 130 and is designed to receive an IP address to the DNS server 221-223 from the DHCP server 130 and to store this address as a part of the configuration settings in the first resolver configuration file 114.
  • the modified DHCP client 215 is also in contrast to traditional DHCP clients 115 designed to store the identity of the corresponding network interface 231-233 in said first resolver configuration file 114.
  • the second resolver configuration file 217 is in contrast to the first resolver configuration file 114 designed to comprise configuration settings related to all DNS servers 221-223 and the corresponding network interfaces 231-233.
  • the DNS manager 216 is further designed to monitor all changes to the first resolver configuration file 114 and whenever the content in the first file 114 is changed (by the DHCP client 215), the DNS manager 216 stores this new content as a part of the configuration settings in the second resolver configuration file 217. When the new content is stored in the second file 217, the DNS manager overwrites the content in the first file 114 with the IP address to the DNS manager 216 itself which also is the default configuration settings in said first file 114.
  • the DNS manager 216 is further designed to monitor all network interfaces 231-233. If for example any of the network interfaces 231-233 becomes unavailable, this is detected by the DNS manager 216 and the second resolver configuration file 217 is updated accordingly. When an interface 231-233 is disabled, the associated DNS data in the DNS manager 216 is also disabled. When a configuration setting (also called an entry) related to a particular DNS server 221-223 in any of the resolver configuration files 114, 217 does not include the identity of the network interface 231-233, then the information is stored as so called global DNS entry. That is that the particular DNS server 221-223 can be reached over any of the network interfaces 231-233.
  • the global DNS entry is optionally associated with a timer Tl supervised by the DNS manager 216.
  • the entry is removed.
  • the timer Tl is reset each time the entry is accessed.
  • the entry is removed when a certain number of failed attempts has been reached.
  • the DHCP client 215 is shut down if the interface 231-233 it was started for goes down. When the DHCP client 215 is shut down it should remove the DNS server 221-223 and other settings it configured. This to avoid unnecessary resolution requests trough the specific network interface 231-233. For this purpose, the DHCP clients 215 add information to the first resolver configuration file 114 with a special null interface. This will result in that DNS manager 216 removes the specified entries from the second resolver configuration file 217.
  • FIG 3 another embodiment of the current invention is illustrated.
  • a same DNS server4 321 can be accessed from a plurality of network interfaces such as interfaces 331 and 332.
  • DNS server4 321 belongs to a network 341 whereas a DNS server5 322 that is accessed from a network interface 333 belongs to a network 342.
  • Figure 3 illustrates another embodiment of the current invention.
  • the DNS manager 216 has three network interfaces 331-333 where network interfaces 331 and 332 are connected to a DNS server, DNSserver4 321 and the network interface 333 is connected to a DNS server, DNSserver ⁇ 321.
  • This embodiment shows how the reliability between the host system 210 and the DNS servers 321,322 can be increased. If the network interface 331 for some reason becomes unavailable 339, resolution requests to DNS server4 321 will be ⁇ re-routed' over network interface 332 instead.
  • the same interface can also access a plurality of DNS servers 321,322.
  • identities of all DNS servers 321,322 are added to the first resolver configuration file 114.
  • the identities are stored in an arbitrary order and the first server 321 in the list is used first and if it doesn't work the next server 322 is tried.
  • FIG. 4 is a flow diagram illustrating the resolution process in the current invention.
  • a resolution request in step 401 (comprising a host name to a desired application server 140) from any of the user clients 111,112 is received by the resolver 113.
  • the resolver 113 determines in step 402 a first IP address IPl by interrogating the first resolver configuration file 114. In file 114 this first IP address IPl (the address to the DNS manager 216) is stored. This first IP address IPl could for example be the IP address of the host 210 itself.
  • the resolution request comprising the host name is passed further in step 403 to the DNS manager 216.
  • the DNS manager 216 analyses the resolution request and determines in step 404 a second IP address IP2 (the address to the DNS server 221-223) by interrogating the second resolver configuration file 217.
  • the second IP address IP2 is stored together with the identities of the corresponding network interfaces 231- 233.
  • the resolution request is passed in step 405 to the relevant DNS server 221-223 over the corresponding network interface 231- 233.
  • the DNS server 221-223 translates the host name to a third IP address IP3 and returns a response with the translated third IP address IP3 which is received in step 406 by the DNS manager 216.
  • the DNS manager 216 further forwards the response to the user client 111,112 which in turn uses the received third IP address IP3 to access the desired application server 140.
  • Figure 5 is a flow chart illustrating the method of updating the first and second resolver configuration files 114, 217.
  • step 502 Whenever the first resolver configuration file 114 is updated in step 501 by the DHCP client 215, these updates are detected in step 502 by the DNS manager 216 and are copied and stored in step 503 to the second resolver configuration file 217. Detection in step 502 of changes to the first resolver configuration file 114 can be implemented in at least two ways. One is to have the DNS manager 216 adapted to regular poll the first resolver configuration file 114.
  • Another way is to use more sophisticated methods such as ⁇ inode' based directory notifications for monitoring possible changes, thus making it possible to keep track of changes without actively polling a storage location.
  • the updated information regarding a particular DNS server 221-223 does not include any identity of a corresponding network interface 231-233 then the information is stored as so called global DNS information in the second resolver configuration file 217. That is that particular DNS server 221-223 can be reached over any of the network interfaces 231-233.
  • the DNS manager 216 After storing in step 503 the updated information in the second resolver configuration file 217, the DNS manager 216 overwrites in step 504 the content in the first resolver configuration file 114 with the first IP address IPl, i.e. the IP address to the DNS manager 216 itself.
  • IPl the first IP address
  • the DNS manager 216 By this last step 504, it is ensured that any following resolution request from any of the user clients 111,112 is directed to the DNS manager and the analysis of this following resolution request is performed in the same way as described above.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Data Exchanges In Wide-Area Networks (AREA)

Abstract

L'invention concerne un système d'ordinateur hôte (210) ayant une pluralité d'interfaces réseau (231 à 233), ledit hôte (210) communiquant avec une pluralité de serveurs de systèmes de noms de domaine, DNS (221 à 223). Un problème lors de la communication avec plus d'un serveur DNS (221 à 223) est que des demandes de résolution provenant de l'ordinateur hôte (210) peuvent être dirigées vers le mauvais serveur DNS (221 à 223). Ceci est dû au fait que le protocole DHCP écrase des données de fichier de configuration de résolveur (114) relatives à un serveur DNS (221) par des données relatives à un autre serveur DNS (222). La présente invention résout ce problème en introduisant un gestionnaire de DNS (216) vers lequel toutes les demandes de résolution sont envoyées dès le départ, le gestionnaire de DNS (216) étant conçu pour garantir que toutes les demandes de résolution sont transférées au bon serveur DNS (221 à 223).
PCT/SE2007/050504 2007-07-05 2007-07-05 Gestionnaire de dns Ceased WO2009005433A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/SE2007/050504 WO2009005433A1 (fr) 2007-07-05 2007-07-05 Gestionnaire de dns

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/SE2007/050504 WO2009005433A1 (fr) 2007-07-05 2007-07-05 Gestionnaire de dns

Publications (1)

Publication Number Publication Date
WO2009005433A1 true WO2009005433A1 (fr) 2009-01-08

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE2007/050504 Ceased WO2009005433A1 (fr) 2007-07-05 2007-07-05 Gestionnaire de dns

Country Status (1)

Country Link
WO (1) WO2009005433A1 (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2605487A1 (fr) * 2011-12-14 2013-06-19 Samsung Electronics Co., Ltd. Procédé de configuration d'adresse de serveur avec nom de domaine et appareil
WO2017083759A1 (fr) * 2015-11-12 2017-05-18 Verisign, Inc. Techniques pour diriger un processus de résolution d'un service de noms de domaine (dns)
US11616788B2 (en) 2016-07-28 2023-03-28 Verisign, Inc. Strengthening integrity assurances for DNS data
US11700230B1 (en) 2016-08-31 2023-07-11 Verisign, Inc. Client controlled domain name service (DNS) resolution
US11831597B1 (en) 2014-12-16 2023-11-28 Verisign, Inc. Balancing visibility in the domain name system
US11882109B2 (en) 2011-10-03 2024-01-23 Verisign, Inc. Authenticated name resolution

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5777989A (en) * 1995-12-19 1998-07-07 International Business Machines Corporation TCP/IP host name resolution for machines on several domains
WO2001029684A1 (fr) * 1999-10-20 2001-04-26 Next Level Communications Interception de demande de serveur de nom de domaine et enregistrement d'adresses url d'installations d'abonnes
US6480508B1 (en) * 1999-05-12 2002-11-12 Westell, Inc. Router-based domain name system proxy agent using address translation
US20030041091A1 (en) * 2001-08-23 2003-02-27 Hughes Electronics Corporation Domain name system resolution

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5777989A (en) * 1995-12-19 1998-07-07 International Business Machines Corporation TCP/IP host name resolution for machines on several domains
US6480508B1 (en) * 1999-05-12 2002-11-12 Westell, Inc. Router-based domain name system proxy agent using address translation
WO2001029684A1 (fr) * 1999-10-20 2001-04-26 Next Level Communications Interception de demande de serveur de nom de domaine et enregistrement d'adresses url d'installations d'abonnes
US20030041091A1 (en) * 2001-08-23 2003-02-27 Hughes Electronics Corporation Domain name system resolution

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11882109B2 (en) 2011-10-03 2024-01-23 Verisign, Inc. Authenticated name resolution
US9210121B2 (en) 2011-12-14 2015-12-08 Samsung Electronics Co., Ltd. Domain name system address configuration method and apparatus
EP2605487A1 (fr) * 2011-12-14 2013-06-19 Samsung Electronics Co., Ltd. Procédé de configuration d'adresse de serveur avec nom de domaine et appareil
US11831597B1 (en) 2014-12-16 2023-11-28 Verisign, Inc. Balancing visibility in the domain name system
US12531828B2 (en) 2014-12-16 2026-01-20 Verisign, Inc. Balancing visibility in the domain name system
US11985105B2 (en) 2015-11-12 2024-05-14 Verisign, Inc. Techniques for directing a domain name service (DNS) resolution process
US11316819B1 (en) 2015-11-12 2022-04-26 Verisign, Inc. Techniques for directing a domain name service (DNS) resolution process
US10791085B2 (en) 2015-11-12 2020-09-29 Verisign, Inc. Techniques for directing a domain name service (DNS) resolution process
WO2017083759A1 (fr) * 2015-11-12 2017-05-18 Verisign, Inc. Techniques pour diriger un processus de résolution d'un service de noms de domaine (dns)
US11616788B2 (en) 2016-07-28 2023-03-28 Verisign, Inc. Strengthening integrity assurances for DNS data
US12388840B2 (en) 2016-07-28 2025-08-12 Verisign, Inc. Strengthening integrity assurances for DNS data
US11700230B1 (en) 2016-08-31 2023-07-11 Verisign, Inc. Client controlled domain name service (DNS) resolution
US12058099B1 (en) 2016-08-31 2024-08-06 Verisign, Inc. Client controlled domain name service (DNS) resolution

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