DNS Service Availability - Testing DNS availability using the DNS Service

Last Modified

Wed Nov 30 19:30 GMT 2022

Description

  • The DNS service is for monitoring the health of a DNS Server
  • Testing a domain name system's (DNS) availability allows you to verify the setup of your DNS, mail queue, and firewalls.
  • The DNS Resolution value is either an IP or the hostname, which can be found under Settings > Properties of the device

Environment

  • N-able N-central

Solution

  • If you want to verify that a device to be monitored has DNS, you can use agent status, which tries to resolve the FQDN of your N-able N-central server when it checks in
  • For example, you can use the telnet command against your N-able N-central server and port number to test the DNS service availability
    • telnet dc.example.local 53
  • A failure would return something similar to the following:
    • Connecting To 192.168.1.1...Could not open connection to the host, on port 53: Connect failed
  • To test the DNS availability from your N-able N-central server, please do the following:
    1. In the left-hand navigation menu, click System Settings > Tools > Test DNS Availability.
    2. Specify the IP address of the DNS Server
      • NOTE: The default is the primary DNS server set for the DNS server being tested.
    3. Specify the Port on which the DNS server is running the DNS service.
    4. Select a Record Type, definitions shown below:
      • A: which is an address record that stores the IP address associated with a domain name. For example: 192.168.40.19
      • MX: which is a mail exchange record that stores the domain name of the mail exchange server. For example: mail.example.com
      • PTR: which is a pointer record that stores the domain name associated with an IP address. For example: example.com
      • Any: which specifies any or all of the record types
    5. In the IP Address/FQDN field, specify the IP address or FQDN to be looked up
      • NOTE: If you are testing using a PTR record, you must specify the IP address in reverse and add a suffix
      • For example, 192.168.40.19 would be 19.40.168.192.in-addr.arpa.
    6. Select Test
  • More information on the DNS service can be found here: /N-central/documentation/Content/Services/Services_DNS.html