Speed Test Mode

SmartDNS can modify the speed test mode and response mode. These two modes affect the performance and results of queries.

Mode	Parameter	Explanation
Speed test mode	speed-check-mode	SmartDNS speed test mode
Response mode	response-mode	Result response mode

Speed test mode configuration

SmartDNS provides two speed test modes, namely ping and tcp. Smartdns defaults to use three tests. The first one is ping, the second one is tcp on port 80, and the third one is tcp on port 443. The speed test mode can be modified through speed-check-mode.

Global speed test mode configuration
```
speed-check-mode ping,tcp:80,tcp:443
speed-check-mode tcp:443,ping
speed-check-mode none
```
Options:
- ping indicates using ping mode, tcp:port number indicates using tcp connection to the corresponding port
- none indicates not to perform speed test
- Trigger of speed test options: When three speed test modes are configured, SmartDNS first uses the first one, 200ms later, the second one is used, and 400ms later, the third one is used.

Single domain speed test mode configuration

domain-rules /example.com/ -speed-check-mode ping,tcp:80,tcp:443

Turn off speed test when querying corresponding ports
```
bind [::]:53 -no-speed-check
```
Extra

If the domain names that need to be routed are forwarded through forwarding programs, consider turning off the speed test function of the forwarding domain name to avoid the reverse effect caused by inconsistent speed tests and exports, and close the speed test of specific domain names as follows:
```
domain-rules /example.com/ -speed-check-mode none
```

Response mode configuration

SmartDNS supports setting the first request response mode through response-mode. These three modes affect the query results and response time, and SmartDNS uses an optimized plan by default, but users can also make modifications as needed. The functions and performance of these three modes are as follows:

Mode	Configuration	Delay	Result	Explanation
Fastest ping response address mode	first-ping	Moderate	Possibly second best	Fastest upstream DNS query delay + shortest ping delay, best query waiting and linking experience (currently the default)
Fastest IP address mode	fastest-ip	Long	Best	The IP address with the shortest ping among all queried IP addresses. The longest DNS query time and the shortest IP link. (Previous mode)
Fastest response DNS mode	fastest-response	Short	Possibly worst	Shortest DNS query waiting time.

For cached data after the cache function is turned on, no matter which mode is used, smartdns will save the best result in the cache, so it is not recommended to close the cache.

Set return mode for specified domain name

In some cases, it may be necessary to set the response mode of a specific domain name to improve the Internet experience. You can configure the following parameters
```
domain-rules /example.com/ -r first-ping
domain-rules /example.com/ -response-mode fastest-response
```