the best practice for using DNS as the SLA probe method

[sean3]

greetings,

Previously we used ping to a single www server from public Internet as the SLA detect method, and some day ISP stops the ICMP to that www server, so SD-WAN rule brought down the member interface.

Now we'd like to use DNS as the active probe method since there are robust public DNS service provider for public Internet.

So, my question is, what is the SLA Target if using DNS? from the screenshot below, it looks the same as measurement to Ping. Isn't it supposed to measure the response time for a DNS query? Should SLA Target be enabled?

Thanks for your any advice！

[spoojary · Accepted solution]

When using DNS as the active probe method for SLA detection in Fortinet's SD-WAN, the SLA target is used to set thresholds for latency, jitter, and packet loss. Even though DNS is used as the protocol, the SLA target settings are still relevant for measuring the quality of the DNS responses.

[sean3]

thanks.

OK the packet loss is to measure how much dns response packet get lost?

latency is to measure how long it takes to get a DNS answer?

how about jitter? does it mean the longest DNS response time minus the shortest DNS response time?

It should not be identical to what ping does right?