Windows DNS Server Interview Questions

> What is DNS ?
The Domain Name System (DNS) is a hierarchical distributed naming system for computers. The Domain Name System distributes the responsibility of assigning domain names and mapping those names to IP addresses by designating authoritative name servers for each domain. Authoritative name servers are assigned to be responsible for their particular domains, and in turn can assign other authoritative name servers for their sub-domains.

>What is the main purpose of a DNS server?
DNS servers are used to resolve FQDN hostnames into IP addresses and vice versa.

>What is the port no of dns ?
53.

>What is a Forward Lookup?
Resolving Host Names to IP Addresses.

>What is Reverse Lookup?
It?s a file contains host names to IP mapping information.

>What is a Resource Record?
It is a record provides the information about the resources available in the N/W infrastructure.

>What are the diff. DNS Roles?
Standard Primary, Standard Secondary, & AD Integrated.

>What is a Zone?
Zone is a sub tree of DNS database.

>Secure services in your network require reverse name resolution to make it more difficult to launch successful attacks against the services. To set this up, you configure a reverse lookup zone and proceed to add records. Which record types do you need to create?
PTR Records

>SOA records must be included in every zone. What are they used for ?
SOA records contain a TTL value, used by default in all resource records in the zone. SOA records contain the e-mail address of the person who is responsible for maintaining the zone. SOA records contain the current serial number of the zone, which is used in zone transfers.

>By default, if the name is not found in the cache or local hosts file, what is the first step the client takes to resolve the FQDN name into an IP address ?
Performs a recursive search through the primary DNS server based on the network interface configuration .

> On which port DNS server works ?
DNS servers use port 53 by default. Incoming and outgoing packets should be allowed on port 53. Also allow connections on port 921 if you configure a lightweight resolver server.

The DNS control utility, rndc, connects to the DNS server with TCP port 953 by default. If you are running rndc on the name server, connections on this TCP port from localhost should be allowed. If you are running rndc on additional systems, allow connections to port 953 (or whatever port you have chosen to configure) from these additional systems.

> What is round robin DNS?
Round robin DNS is usually used for balancing the load of geographically distributed Web servers. For example, a company has one domain name and three identical home pages residing on three servers with three different IP addresses. When one user accesses the home page it will be sent to the first IP address.

The second user who accesses the home page will be sent to the next IP address, and the third user will be sent to the third IP address. In each case, once the IP address is given out, it goes to the end of the list. The fourth user, therefore, will be sent to the first IP address, and so forth.

> What is primary, Secondary, stub & AD Integrated Zone?
Primary Zone: - zone which is saved as normal text file with filename (.dns) in DBS folder. Maintains a read, write copy of zone database.

Secondary Zone: - maintains a read only copy of zone database on another DNS server. Provides fault tolerance and load balancing by acting as backup server to primary server.

Stub zone: - contains a copy of name server and SOA records used for reducing the DNS search orders. Provides fault tolerance and load balancing.

> How do you manually create SRV records in DNS?
This is on windows server go to run ---> dnsmgmt.msc rightclick on the zone you want to add srv record to and choose "other new record" and choose service location(srv).

> What is the main purpose of SRV records ?
SRV records are used in locating hosts that provide certain network services.

> Before installing your first domain controller in the network, you installed a DNS server and created a zone, naming it as you would name your AD domain. However, after the installation of the domain controller, you are unable to locate infrastructure SRV records anywhere in the zone. What is the most likely cause of this failure ?
The zone you created was not configured to allow dynamic updates. The local interface on the DNS server was not configured to allow dynamic updates.

> What is Name Server?
A name server keeps information for the translation of domain names to IP addresses and IP addresses to domain names. The name server is a program that performs the translation at the request of a resolver or another name server.

> What is Primary name server or primary master server?
Primary name server/primary masteris the main data source for the zone. It is the authoritative server for the zone. This server acquires data about its zone from databases saved on a local disk. The primary server must be published as an authoritative name server for the domain in the SOA resource record, while the primary master server does not need to be published.

>What is Secondary name server/slave name server?
Secondary name server/slave name server acquires data about the zone by copying the data from the primary name server (respectively from the master server) at regular time intervals. It makes no sense to edit these databases on the secondary name servers, although they are saved on the local server disk because they will be rewritten during further copying.

> Which of the following conditions must be satisfied to configure dynamic DNS updates for legacy clients ?
The zone to be used for dynamic updates must be configured to allow dynamic updates. The DHCP server must support, and be configured to allow, dynamic updates for legacy clients.

> At some point during the name resolution process, the requesting party received authoritative reply. Which further actions are likely to be taken after this reply ?
After receiving the authoritative reply, the resolution process is effectively over.

> Name 3 benefits of using AD-integrated zones.
Active Directory integrated DNS enables Active Directory storage and replication of DNS zone databases. Windows 2000 DNS server, the DNS server that is included with Windows 2000 Server, accommodates storing zone data in Active Directory.

When you configure a computer as a DNS server, zones are usually stored as text files on name servers that is, all of the zones required by DNS are stored in a text file on the server computer.

These text files must be synchronized among DNS name servers by using a system that requires a separate replication topology and schedule called a zone transfer However, if you use Active Directory integrated DNS when you configure a domain controller as a DNS name server, zone data is stored as an Active Directory object and is replicated as part of domain replication.

> What is Root name server?
Root name server is an authoritative name server for the root domain (for the dot). Each root name server is a primary server, which differentiates it from other name servers.