URL : 6 Couldn't resolve host name

Products

• DX Unified Infrastructure Management (Nimsoft / UIM)

Issue/Introduction

We receive url alerts of 6 Couldn't resolve host name error for specific urls on different servers. And there were no changes made to the urls and when the alert came the urls were accessible. We checked all URLs and it was working very well.  Why there was a fluctuation? Its not for one app, its for multiple and there were no changes. Kindly let us know the reason why it happened.

Environment

Release : 9.0.2

Component : UNIFIED INFRASTRUCTURE MGMT

Cause

- Changes in DNS

Resolution

Please make sure you're running url_response GA version 4.52.

The underlying mechanism is curl so this is a curl error 6.

Something in DNS must have changed for these hosts or the local machine is not connecting to the same DNS server, check via ipconfig /all.

If on the local machine where url_response is running you cannot resolve the host(s) via nslookup, try adding one or more IP/Hostname/Alias entries into the /local etc/hosts file to workaround it.

Its also possible that a proxy was introduced/configured on the machine hosting the probe. You can also verify that by trying resolving the url via the command line. If you cannot resolve the the URL from the command line but can navigate to the URL using a browser, then most likely there is a proxy in the middle. 

The probe supports proxies and user authentication for accessing the requested web URL.

https://techdocs.broadcom.com/us/en/ca-enterprise-software/it-operations-management/ca-unified-infrastructure-management-probes/GA/alphabetical-probe-articles/url-response-url-endpoint-response-monitoring/url-response-im-configuration.html

Root cause in this case was due to DNS changes.