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This product reached the end of support date on March 31, 2021.

FqdnResolutionException:Cannot resolve FQDN for IP xx.xx.xx.xx

wentao_huang
Inactive

I can see such a warning in the dynatrace server log from time to time,WARNING[CachingFqdnResolver]Failed ro resolve DNS for IP "xx.xx.xx.xx"-had following exception:com.dynatrace.diagnostics.sdk.net.FqdnResolutionException:Cannot resolve FQDN for IP xx.xx.xx.xx.

The following message appears before that,agent unregistered from collector .Sometimes the fault can return to normal in 0 seconds, sometimes for several minutes.What does this mean and where is the problem? I am looking forward your reply.Thank you.

4 REPLIES 4

Radu
Dynatrace Pro
Dynatrace Pro

Hi Hanley,

It looks like the Dynatrace Server is having issues performing reverse DNS lookups. It's trying to figure out what domain is associated with that IP address but cannot resolve it.

Try logging into the server machine and performing an "nslookup" on the IP addresses that appear in the log warnings.

Also... do you recognise the IP address? Is it a collector? or an agent?

Regards,

Radu

It's an agent.Do I need to config the DNS in the Dynatrace server's file /etc/hosts ?

Why does the collector connect to the agent through reversing DNS, rather than directly through the IP?

This shouldnt be a problem. OUr agents simply try to resolve the full qualified domain name of the agent. this name will eventually show up in dynatrace in case we get the name. if we cant query it we simply just show the host name or the IP Address

tarjei_utnes
Organizer

I am seeing this message on some of our collectors, which means that they are changing hostnames every now and then.

Is there anywhere to set this statically?