Hello

I would like to receive alerts on any failed DNS lookups- i.e. an endpoint in my environment attempts to connect with a domain name that could not be resolved - i.e. domain does not exist.

Is this possible with PRTG?

Thank you Tony

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Hi specialist,

You can use a simple ping sensor for this.
Have the parent device point at the DNS name, if it cannot be resolved, the ping will fail.


Nov, 2015 - Permalink

Thank you.

I will try this :-)

BTW - is it possible that the domain's firewall or boundary router will be configured to reject ICMP traffic - assuming ICMP ping is what you're referring to?


Nov, 2015 - Permalink

Absolutely, routers cen be setup to drop ICMP when they get too busy.

But you can also use a http sensor if you like as long as you use a DNS name.


Nov, 2015 - Permalink

Thank you again.

The goal is not ad-hoc active checks. We need to alert on DNS failures as a result of a look up by any endpoint.

We could use Wireshark to sniff traffic and apply a filter to show up DNS failure messages. these can then be investigated.

Thanks Tony


Nov, 2015 - Permalink