msgid "" msgstr "" "Project-Id-Version: Vietnamese (cnp3-ebook)\n" "Report-Msgid-Bugs-To: \n" "POT-Creation-Date: 2026-04-18 21:37+0200\n" "PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n" "Last-Translator: FULL NAME \n" "Language-Team: Vietnamese \n" "Language: vi\n" "MIME-Version: 1.0\n" "Content-Type: text/plain; charset=UTF-8\n" "Content-Transfer-Encoding: 8bit\n" "Plural-Forms: nplurals=1; plural=0;\n" "X-Generator: Weblate 5.14.3\n" #: ../../principles/naming.rst:82 msgid "" "This hierarchical naming scheme is a key component of the Domain Name System " "(DNS). The DNS is a distributed database that contains mappings between " "fully qualified domain names and addresses. The DNS uses the client-server " "model. The clients are hosts or applications that need to retrieve the " "mapping for a given name. Each :term:`nameserver` stores part of the " "distributed database and answers the queries sent by clients. There is at " "least one :term:`nameserver` that is responsible for each domain. In the " "figure below, domains are represented by circles and there are three hosts " "inside domain `dom` (`h1`, `h2` and `h3`) and three hosts inside domain " "`a.sdom1.dom`. As shown in the figure below, a sub-domain may contain both " "host names and sub-domains." msgstr "" #: ../../principles/naming.rst:107 msgid "" "A :term:`nameserver` that is responsible for domain `dom` can directly " "answer the following queries :" msgstr "" #: ../../principles/naming.rst:109 msgid "" "the address of any host residing directly inside domain `dom` " "(e.g. `h2.dom` in the figure above)" msgstr "" #: ../../principles/naming.rst:110 msgid "" "the nameserver(s) that are responsible for any direct sub-domain of domain " "`dom` (i.e. `sdom1.dom` and `sdom2.dom` in the figure above, but not " "`z.sdom1.dom`)" msgstr "" #: ../../principles/naming.rst:112 msgid "" "To retrieve the mapping for host `h2.dom`, a client sends its query to the " "name server that is responsible for domain `.dom`. The name server directly " "answers the query. To retrieve a mapping for `h3.a.sdom1.dom` a DNS client " "first sends a query to the name server that is responsible for the `.dom` " "domain. This nameserver returns the nameserver that is responsible for the " "`sdom1.dom` domain. This nameserver can now be contacted to obtain the " "nameserver that is responsible for the `a.sdom1.dom` domain. This nameserver " "can be contacted to retrieve the mapping for the `h3.a.sdom1.dom` name. " "Thanks to this structure, it is possible for a DNS client to obtain the " "mapping of any host inside the `.dom` domain or any of its subdomains. To " "ensure that any DNS client will be able to resolve any fully qualified " "domain name, there are special nameservers that are responsible for the root " "of the domain name hierarchy. These nameservers are called :term:`root " "nameserver`." msgstr "" #: ../../principles/naming.rst:114 msgid "" "Each root nameserver maintains the list [#froot]_ of all the nameservers " "that are responsible for each of the top-level domain names and their " "addresses [#frootv6]_. All root nameservers cooperate and provide the same " "answers. By querying any of the root nameservers, a DNS client can obtain " "the nameserver that is responsible for any top-level-domain name. From this " "nameserver, it is possible to resolve any domain name." msgstr "" #: ../../principles/naming.rst:117 msgid "" "To be able to contact the root nameservers, each DNS client must know their " "addresses. This implies, that DNS clients must maintain an up-to-date list " "of the addresses of the root nameservers. Without this list, it is " "impossible to contact the root nameservers. Forcing all Internet hosts to " "maintain the most recent version of this list would be difficult from an " "operational point of view. To solve this problem, the designers of the DNS " "introduced a special type of DNS server : the DNS resolvers. A " ":term:`resolver` is a server that provides the name resolution service for a " "set of clients. A network usually contains a few resolvers. Each host in " "these networks is configured to send all its DNS queries via one of its " "local resolvers. These queries are called `recursive queries` as the " ":term:`resolver` must recursively send requests through the hierarchy of " "nameservers to obtain the `answer`." msgstr "" #: ../../principles/naming.rst:119 msgid "" "DNS resolvers have several advantages over letting each Internet host query " "directly nameservers. Firstly, regular Internet hosts do not need to " "maintain the up-to-date list of the addresses of the root servers. Secondly, " "regular Internet hosts do not need to send queries to nameservers all over " "the Internet. Furthermore, as a DNS resolver serves a large number of hosts, " "it can cache the received answers. This allows the resolver to quickly " "return answers for popular DNS queries and reduces the load on all DNS " "servers [JSBM2002]_." msgstr "" #: ../../principles/naming.rst:123 msgid "Benefits of names" msgstr "" #: ../../principles/naming.rst:127 msgid "" "if the server process moves to another physical server, all clients must be " "informed about the new server address" msgstr "" #: ../../principles/naming.rst:128 msgid "" "if there are many concurrent clients, the load of the server will increase " "without any possibility of adding another server without changing the server " "addresses used by the clients" msgstr "" #: ../../principles/naming.rst:139 msgid "Footnotes" msgstr "" #: ../../principles/naming.rst:140 msgid "" "The :term:`hosts.txt` file is not maintained anymore. A historical snapshot " "from April 1984 is available from http://ftp.univie.ac.at/netinfo/netinfo/" "hosts.txt" msgstr "" #: ../../principles/naming.rst:142 msgid "" "See http://www.donelan.com/dnstimeline.html for a time line of DNS related " "developments." msgstr "" #: ../../principles/naming.rst:144 msgid "" "This specification evolved later to support domain names written by using " "other character sets than us-ASCII :rfc:`5890`. This extension is important " "to support languages other than English, but a detailed discussion is " "outside the scope of this document." msgstr "" #: ../../principles/naming.rst:146 msgid "" "The official list of top-level domain names is maintained by :term:`IANA` at " "http://data.iana.org/TLD/tlds-alpha-by-domain.txt Additional information " "about these domains may be found at http://en.wikipedia.org/wiki/" "List_of_Internet_top-level_domains" msgstr "" #: ../../principles/naming.rst:148 msgid "" "A copy of the information maintained by each root nameserver is available at " "http://www.internic.net/zones/root.zone" msgstr "" #: ../../principles/naming.rst:152 msgid "" "It is interesting to note that to prevent any homograph attack, Google Inc. " "registered the `g00gle.com` domain name but does not apparently use it." msgstr ""