Windows palvelimena, DNS, e1

Tehtävänanto:
E1
1.1. Selvitä mitä on / mitä seuraavilla tarkoitetaan
nimipalvelun komponentit (DNS components)
nimipalvelimen erilaiset “roolit”
resurssitietueet (resource records)
SOA, A, PTR, NS, CNAME, SRV, MX?
autoratiivinen nimipalvelin?
resolvoiva nimipalvelin?
– vyöhyke (zone) versus domain yhteydet / eroavuudet?

1.2
Selvitä, miten nimenselvitys toimii. Anna sopivat esimerkit sen toiminnasta.

Palauta etätehtävä nimettynä omalla nimelläsi seuraavasti: (Sukunimi_Etunimi_E1.doc tai Sukunimi_Etunimi_E1.pdf) tehtävän palautuskohtaan (Lisää palautus).


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1.1
DNS,
Domain name system (nimipalvelujärjestelmä) is a distributed hierarchical naming system for any devices connected to internet or private network. The system provides the translation of easily memorisable domain names to the numerical IP addresses to locate computer services and devices worldwide.

# nimipalvelun komponentit
– association of domains, subdomains and hosts.

  • Domain name space, “a tree of domain names”.
  • Name servers (authoritative name servers, master & slave, and recursive name servers).

# nimipalvelimen erilaiset “roolit”
a. resolvoiva nimipalvelin (samassa lähiverkossa tai organisaatiossa olevat laitteet voivat kysyä siltä palvelimelta mitä tahansa nimipalvelukysymyksiä)
b. autoratiivinen nimipalvelin (sisältää vähintään yhden verkkotunnuksen tiedot ja josta resolvoivat palvelimet voivat kysyä tuohon vyöhykkeeseen liittyviä tietoja).

## resurssitietueet (resource records)
DNS records (or Zone files) are used for mapping URLs to an IPs.
Thus, modifying your DNS settings (to add sub-domains, redirect e-mail and control other services) is done when editing the zone file on the DNS server.

## SOA, A, PTR, NS, CNAME, SRV, MX
Different record types are used for different purposes in domain servers.

Possible record types (are contained in the zone file):

Start of Authority (SOA) – This is one larger record at the beginning of every zone file with the primary name server for the zone and some other information.

Address Record / Host (A) – This is the basic mapping of IP address to host name, assigning an IP address to a domain or subdomain name.

Pointer record (PTR) for setting the IP address X.X.X.X resolving (reverse DNS record) to the domain yourdomain.example.com.

Name Server (NS) – This contains the name server information for the zone. If you configure this, your server will let other DNS servers know that yours is the ultimate authority (SOA).

The Canonical Name (CNAME) is an alias for your domain. Anyone accessing that alias will be automatically directed to the server indicated in the A record.

A Service record (SRV record) defines the location (i.e. the hostname and port number) of servers for specified services (e.g., Session Initiation Protocol (SIP) and XMPP often require SRV support by network elements).

A mail exchanger (MX) record allows you to point your mail services somewhere other than your hosting company (Google Apps for your domain).

## autoratiivinen nimipalvelin
An authoritative name server lets recursive name servers know what DNS data (the IPv4 IP, the IPv6 IP, a list of incoming mail servers, etc.) a given host name (such as “www.example.com”) has.

## resolvoiva nimipalvelin
tuntee DNS-puun rakenteen ja osaa selvittää vastaukset kysymyksiin.

## vyöhyke (zone) versus domain yhteydet / eroavuudet

1.2
# Miten nimenselvitys toimii
a. “www.URL-address.com typed into browser and OK pressed”
b. The browser communicates with a name server to translate the server name “www.URL-address.com” into an IP Address.
c. The resolved IP address is used to connect to the server machine. The server sends the HTML text for the Web page to the browser (www.URL-address.com/index.html).
d.?!???
…PROFIT!

Links to explore further:

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