DNS Monitor

The DNS monitor supports the following Resource Records:
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Resource Records
The DNS monitor supports the following Resource Records:
  • A
    Address
  • AAAA
     
    IPv6 Address
  • MX
    Mail Exchange
  • NS
     
    Name Server
  • CNAME
     
    Canonical Name
  • PTR
     
    Pointer
  • SOA
     
    Start of Authority
  • TXT
     
    Text
Configure DNS Monitor
DNS monitors have the following configuration options:
  • Record Type
    Defines the Resource Record that you want to query.
  • (Optional) Expected Result
    Signifies the expected answer of the DNS server. If set, the answer of the queried DNS server matches against the setting.
  • Number of Retries
    Sets the number of unanswered requests that the monitor waits for.
  • Use TCP Instead of UDP
    Enables communication through the TCP protocol.
  • DNS Servers
    Specifies the server that the tests query. Select one of the following options:
    • Local
      Uses a local DNS resolver (with cache) on the Point of Presence to monitor the experience of a real user. This option mimics the lookup behavior of a local user.
    • As Listed by DNS
      Queries all the name servers that are listed in the NS records for 
      hostname
      .
    • Custom
      Lets you enter a custom list of name servers to query. Enter the IP addresses of the servers in a comma-separated list.
    • Minimum
      Specifies the minimum number of servers that respond to the monitor.
DNS Monitor Workflow
The following diagram shows the DNS monitor workflow:
DNS Monitor Workflow
DNS monitor workflow
Collected Metrics Process
The following diagram shows the metric collection process of the DNS monitor:
DNS Monitor Metrics
DNS Monitor Metrics
Collected Metrics
 
Metric Name
 
 
Unit
 
 
Description
 
Resolve Time ( 
rtime
 )
Milliseconds
The time to retrieve the 
NS
 Resource Record
This metric is applicable only when you select the 
As Listed
 option.
Query Time ( 
qtime
 )
Milliseconds
The time to query one 
NS
 
Processing Time ( 
ptime
 )
Milliseconds
The duration of the fastest response
Query Time ( 
dtime
 )
Milliseconds
The average duration of all 
NS
 lookups
Download Size ( 
dsize
 )
Bytes
The average size of all 
NS
 responses
Error Messages
For more information about possible error messages, see Error Messages.