DNS Health Monitor
This article covers the specific configuration for DNS health monitor type. Refer Overview of Health Monitors article for general monitor information, implementation, and other monitor types.
The DNS health monitor validates the health of DNS servers by sending a UDP DNS request and comparing the response IP address.
Configuring General Monitor
- Send Interval - Frequency at which the health monitor initiates a server check in seconds.
- Receive Timeout - Maximum amount of time before the server must return a valid response to the health monitor in seconds.
- Successful Checks - Number of consecutive health checks that must succeed before Avi Vantage marks a down server as being back up.
- Failed Checks - Number of consecutive health checks that must fail before Avi Vantage marks an up server as being down.
Configuring DNS Monitor
A DNS Monitor queries Name Servers for a record and matches the resolved response against an expected IP address.
- Request Name - Fully qualified resource record to be checked, such as, www.avinetworks.com.
- Response Matches - The following are the types of response matches:
- Anything - Any DNS answer from the server will be successful, even an empty answer.
- Any Type - The DNS response must contain at least one non-empty answer.
- Query Type - The response must have at least one answer of which the resource record type matches the query type.
- Response Code - The following are the types of response codes:
- Anything - The DNS server’s response code, and any potential errors are ignored and will not result in a health check failure.
- No Error - An error in the DNS response results in a health check failure.
- Response String - The DNS response must contain this IP address to be considered successful.