Chapter 3

Scavenging

What is the mechanism to remove stale resource records?

Scavenging AND Aging

These must be enabled at the DNS and on the zone

No-refresh interval

The time between the most recent refresh of a record time stamp and the moment when the time stamp can be refreshed again.

Refresh interval

The time between the earliest moment when a record time stamp can be refreshed and the earliest moment when the record can be scavenged.

14 Days

If default values are used, a DNS record becomes eligible for scavenging after the no-refresh and refresh intervals have elapsed, which is how many days?

DNS zone database

What is made up of a collection of resource records, which are used to answer DNS queries.

Start of Authority (SOA) and Name Server (NS)

When you create a new zone, what two types of records are automatically created?

Host (A and AAAA) record

What resource record maps a domain/host name to an IP address?

Canonical Name (CNAME) record

What record maps an alias DNS domain name to another primary or canonical name?

Pointer (PTR) record

What record maps an IP address to a domain/host name?

Mail Exchanger (MX) record

What record maps a DNS domain name to the name of a computer that exchanges or forwards email for the domain?

Service Location (SRV) record

What record maps a DNS domain name to a specified list of host computers that offer a specific type of service, such as Active Directory domain controllers?

The reverse lookup zone

What zone are the PTR records located in?

Contains the name of the primary DNS server authoritative for the zone.

In the SOA properties box, what is the meaning of "Authoritative server

Shows the email address of the administrator who is responsible for the zone. Instead of using the at (@) symbol, it uses a period ( . ).

In the SOA properties box, what is the meaning of "Responsible person

Shows the version or how many times the zone has been updated

In the SOA properties box, what is the meaning of "Serial number

Determines how often the secondary server for the zone checks to see whether the zone data is changed.

In the SOA properties box, what is the meaning of "Refresh shows

After sending a zone transfer request, determines how long (in seconds) the zone's secondary server waits before sending another request.

In the SOA properties box, what is the meaning of "Retry

After a zone transfer, determines how long (in seconds) the zone's secondary server continues to respond to zone queries before discarding its own zone as invalid.

In the SOA properties box, what is the meaning of "Expire

Specifies a default Time to Live (TTL) value, which defines the default time. A resource record remains in a DNS cache after a DNS query has retrieved a record. If a resource record has its own TTL value, the TTL value of the resource record is used instead of the TTL defined in the SOA record. (View Advanced)

In the SOA properties box, what is the meaning of "Minimum TTL

the Name Server (NS) resource record

What record identifies a DNS server?

An Unknown Record

What is a resource record called when the DNS server does not know its RDATA format?

The format for an SRV record

Service_Protocol.Name [TTL] Class SRV Priority Weight Port Target

The SRV format to log on with Lightweight Directory Access Protocol (LDAP)

_ldap._tcp.dc._msdcs.contoso.com SRV 100 0 389dc1.contoso.com.

GlobalNames

What is the preferred method for achieving single-label name resolution?