What is Domain Name System (DNS)?
Domain Name System is a service to resolve the Name to IP Address and IP Address to Name, DNS also used to locate servers, computers and services on your network and DNS is backbone of Active Directory that can be installed on windows server as a standalone or Domain Controller
What is Static and Dynamic DNS Record?
Manually created DNS entry called static record and the record created automatically by the system/DHCP itself called Dynamic DNS Record, static records are not easy to manage as the IP adress changes will not update automatically, we have to update manually
What is Dynamic DNS (DDNS)?
Dynamic DNS or DDNS is a method of updating a DNS record, DDNS is preferred most of the organization since it’s easy to maintain and you always get the latest updated IP address of the servers and computers
What are the record types in DNS?
DNS has many types of records, A record or host records are mostly known to everyone, will explain all the record types in DNS
A (Address) Maps a host name to an IP address, Compute1 pointing to 192.168.100.100, When a computer has multiple adapter cards and IP addresses, it should have multiple address records.
CNAME (Canonical Name) Sets an alias for a host name. Record pointing to different record like www.support.windowstricks.in can have an alias as www.windowstricks.in, so both the records are pointing to same page
MX (Mail Exchange) Specifies a mail exchange server for the domain, used for mail delivery which allows mail to be delivered to the correct mail servers
NS (Name Server) Specifies a name server for the domain, which is authoritative servers for the respective DNS Zone and allows DNS lookups within all DNS zones
PTR (Pointer) Creates a pointer that maps an IP address to a host name for reverse lookups.
SOA (Start of Authority) Declares the host that is the most authoritative for the zone and, as such, is the best source of DNS information for the zone. Each zone file must have an SOA record (which is created automatically when you add a zone)
What is Caching Only Server?
Caching-only servers are those DNS servers that only perform name resolution queries, cache the answers, and return the results to the client. Once the query is stored in cache, next time the query in resolved locally from cached instead of going to the actual site.
What are a Forward and Reverse Lookup?
- Forward Lookup: Searching for A record, all the name query is send to the DNS server against to IP address, it is generally said a forward lookup.
- Reverse Lookup: Searching for PTR records whicho provides a reverse lookup process, enabling clients to use a known IP address during a name query and look up a computer name based on its address
What is Primary DNS zone?
This is the read and writable copy of a zone file in the DNS namespace. This is primary source for information about the zone and it stores the master copy of zone data in a local file or in AD DS. Dy default the primary zone file is named as zone_name.dns in Windows\System32\DNS folder on the server
If its AD integrated zone then all the records are stored in Domain partition on the Domain Controllers
What id Secondary DNS zone?
This is the read only copy of a zone file in the DNS namespace. This is secondary source for information about the zone and it get the updated information from the master copy of primary zone. The network access must be available to connect with primary server. As secondary zone is merely a copy of a primary zone that is hosted on another server, and secondary zone cannot be stored in AD
What is stub DNS Zone?
A stub zone is a read only copy of a zone that contains only those resource records which are necessary to identify the authoritative DNS servers for that particular zone, stub zone also used like DNS Forwarding and its practically used to resolve names between separate DNS namespaces. This type of zone is generally created when a corporate merger or acquire and DNS servers for two separate DNS namespaces resolve names for clients in both namespaces.
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A stub zone contains:
The start of authority (SOA) resource record, name server (NS) resource records, and the glue A resource records for the delegated zone.
The IP address of one or more master servers that can be used to update the stub zone
What is Aging and Scavenging?
To know more about Windows DNS Scavenging Interview Questions and Answers