By default, Jenkins runs on port number 8080.

There are scenarios where Tomcat is running on 8080, or any other application is running on 8080 port. In such cases, to avoid port conflicts you need to change the Jenkins port.

Let's change a port on which Jenkins runs:

1. If you run Jenkins using the command line, then you can execute a command such as java -jar -httpPort=9999 jenkins.war to change the existing port from 8080 to 9999.
2. Another way to change the port while Jenkins is installed using the Windows package is as follows:

• • Go to the Program Files/Jenkins directory where you installed Jenkins
  • Open the Jenkins.xml in the editor
  • Find "--httpPort=8080" and replace the port 8080 with the new port number

First, you installed a virtual image of Ubuntu, changed the password so that it is harder for others to log in, and updated the guest OS for security patches.