RegEx Validation for DNS SOA seems inverted?

Grafana Cloud
1

I’ve been experimenting with Synthetic Monitoring (awesome feature!), and set up 12 DNS checks with RegEx Validation for SOA (e g gustavsson.se).

I’ve set them all to match the RNAME “magnus.gustavsson.net.” for “Validate Answer matches”. All of them fail, expect the one that DOESN’T contain “magnus.gustavsson.net.” (i e gustavsson.uk).

% host -t soa gustavsson.se.
gustavsson.se has SOA record ns1.gustavsson.net. magnus.gustavsson.net. 2019100300 28800 7200 4233600 86400
% host -t soa gustavsson.uk.
gustavsson.uk has SOA record ns-1722.awsdns-23.co.uk. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400
%

I had expected gustavsson.uk to be the only one that fails, since the SOA doesn’t match my expression.

I figure I might have misunderstood the format, so that I, for example, have to add “.*” in the beginning and end to match the entire string. But in that case I would have expected ALL checks to fail. I fail to understand why gustavsson.uk is the only one to validate.

1 Like
2

And, no I haven’t checked the “Invert Match” box. If I do the check turns green.

3

Hey @maggu! It looks like this was a recently resolved bug:

If you are still seeing this issue, please open a Support ticket so our team can further review!

4

Thanks! Didn’t know Synthetic Monitoring has a GitHub repository.

As I thought then, but good to know for sure what’s going on.

Not the solution I would have preferred perhaps (since double negations aren’t very user friendly, and in most cases you probably want the regex to match), but I can certainly see why it was chosen.