Synthetic monitors and DNS

Hi. We recently had a DNS DDoS attack against our DNS host. This led to the DNS host suspending/rate limiting hosting of our zone(s) because they were flooded. The synthetic monitoring against our various domains didn’t report any problems.

I assume that New Relic synthetic agents cache DNS according to TTL and don’t do a DNS root lookup every time? Is this right? Is there any other solution we might use to monitor our DNS availability?

Hi @it.hq_core ,
Here is a post that explains how our Synthetics DNS caching is set: Is there an issue with Synthetics DNS lookup? - #3 by kmullaney

To avoid not being alerted if a DNS issue occurs, you can set up a Scripted API monitor that asynchronously executes multiple DNS lookups against a DNS server. Here you can find a sample code: New Relic Quickstarts

I hope this helps!

Thank you! That really did help and now am able to query the DNS.

The next problem is that the script produces a “Monitor produced no traffic” result, which causes the synthetic test to fail. I’ve seen a few topics that say this is because the built-in request and http objects are not used, but can’t see how I can override this?

Any help gratefully received. Thanks in advance.

“Monitor produced no traffic”

Hi, @it.hq_core: You just need to include a dummy $http.get() request in your script.