1.8 Explain the functions of Network Services part 1 (Domain Name Service)

DNS has different type of entries in its database,Try to list from the top of your head the ones you remember

A record MX record CNAME record SOA NS SRV PTR AAAA TXT

Dynamic Domain Name System DDNS

a newer system that enables hosts to be dynamically registered with the DNS server. it makes changes in real time to host names, ip addresses, and relative info

(NS) Name Server records

stores information that identifies the name servers in the domain that stores information for that domain

(TXT) Text

holds machine readable data such as SPF (Sender Policy Framework), and DKIM (DomainKeys Identified Mail)

DNS namespace

All of the information in the DNS databases - including the top-level domain, country code top-level domain, domain name, and IP address information.

Internal DNS

DNS Servers operated by a company or organization own IT department. this is necessary for large, complex, multi-platform network

DNS Hierarchy

DNS uses this to manage its distributed database system.Also called the domain name space, is an inverted tree structure The DNS tree has a single domain at the top of the structure called the root domain. A period or dot (.) is the designation for the root domain. Below the root domain are the top-level domains that divide the DNS hierarchy into segments such as .com, .org, .edu, .net,gov. Below the top-level domains, the domain name space is further divided into subdomains representing individual organizations. example microsoft, google, yahoo etc

top-level domain

Domains (including .net, .org, .com, .mil. and the set .xx country codes) at the end of a domain name are the highest level of the domain name hierarchy.

DNS (Domain Name System)

The Internet's system for converting alphabetic names into numeric IP addresses. uses port 53 this name resolution system makes it possible to refer to websites and computers or other devices by easy to remember host names ibstead of hard to remember IP addresses

What is the difference between DNS and DDNS?

in DNS entries and changes to entries must be manually performed unlike DNS DDNS enable hosts to dynamically register with the dns so that changes to the dns server entries are changed in real time all in all DDNS has a less likelihood of not finding a server or site that has recently been added or changed

(A) address record

maps a host name to a IP address for IPv4 (32 bit) address

(AAAA) record

most commonly used to map host names to an ip address for a host. remember this stores information for IPv6 (128 bit) addresses

(WINS) Windows Internet Name Service

on Windows networks, A name resolution service that resolves NetBIOS names to IP addresses so that systems can locate and access each other using the easier to remember NETBIOS name rather than the IP address

Third party/Cloud hosted DNS

this DNS type is an alternative to hosting your own DNS servers on premises or using other third party DNS services. For customers with 1,000s to 10,000 or more zones major network operating system vendors such as google offer DNS Server applications this option is low latency, high availability and cost effective

(PTR) Pointer Record

used for reverse lookups, to provide a host name when you know its IP address

(SRV)ervice Locator

A DNS record that specifies a generic service location record for newer protocols. ex. how MX is specifically for email, this is just a broad catch all type of organizational unit

(CNAME) Canonical Name

In a DNS record, this is the information that is most commonly used for additional hostnames, aliases, or nicknames It gives a single computer multiple alias names.

SOA (start of authority) record

a record of information on DNS zones. DNS Zone is part of domain for which an individual DNS Server is responsible

DNS client

systems that ask dns servers for a host name to ip address mapping. The client is also called the resolver. (14)

compare Forward versus Reverse Lookup

the most common type of DNS zone is the forward lookup xone that uses A Record. which allows clients to obtain information such as ip addresses that correspond to domain names. Reverse lookup is the opposite, it uses PTR records to obtain information about host names by using the ip address so remember if you need the ip address but only have the host name you are tring to do a forward lookup if you have the ip address of a system or website but wish for its name you are doing a reverse lookup

External DNS

using the DNS capabilities of the user's Internet Service Provider