The DNS (PI_DNS) record stores information about DNS service response time. This is a multi-instance record.

Item	Default value	Changeable
Collection Interval	360	Y
Collection Offset	0	Y
Log	No	Y
LOGIF	(Blank)	Y

PI_DNS_MSR_COND_ID

None

• Fixed part: 681 bytes
• Variable part: 180 bytes

View name (Manager name)	Description	Summary rule	Format	Delta	Data source
Total Amount of Data (TOTAL_DATA_SIZE)	Total amount of data transferred between the DNS probe and the measurement-target server on UDP (bytes)	AVG	double	No	Probe Daemon
Total Response Time (TOTAL_RESP_TIME)	Total response time (seconds) ((1) in Figure 9-2)	AVG	double	No	Probe Daemon

The following figure shows the DNS sequence.

Figure 9-2 DNS sequence

A DNS probe queries the DNS server for the IP address of the specified search-target host name, and measures the time required for receiving the response.

The following describes and provides notes on a DNS operating environment.

Retry timeout value

The retry timeout value is determined automatically by the following formula:

Retry timeout value = timeout value/(retries count + 1)

Resolution of search-target host name

Measurement fails if the IP address cannot be obtained due to an error in resolving the search-target host name.

RFC compliance

• RFC1034: Domain Names - Concepts and Facilities
• RFC1035: Domain Names - Implementation and Specification
• For the functions that are not compliance with RFCs and the restrictions, see the above notes.