Fix VPN hostname resolution by flushing your DNS cache

Sometimes when my VPN connection to work goes down, certain applications that rely on intranet servers (e.g. Lotus Notes, Lotus Sametime) become unable to reconnect to their servers even after I reconnect to VPN. This is due to the operating system’s DNS lookup cache reusing the failed hostname lookup from when VPN was down rather than doing a fresh hostname lookup now that there is a fresh VPN connection.

On Windows, you can fix the issue by opening up the Command Prompt as Administrator and running the following command:

ipconfig /flushdns

Published by

Leons Petrazickis

I'm a full-stack developer at IBM Digital Business Group. I do Ruby, Node, Python, Hadoop, Spark, as well as web scale devops with Docker and Terraform. My opinions are my own.