Jenkins has a very unique favicon, and when converted into hash form, it becomes 81586312. This hash can be used to identify a Jenkins installation; it can even be used on Shodan to identify systems running Jenkins.

The following screenshot shows how the hash value is used to identify Jenkins:

We can also use different Jenkins HTTP response headers to find the Jenkins instance. For example, to find a specific version of Jenkins, we can use the X-Jenkins header, as shown in the following screenshot:

Let's see what other HTTP response headers we can use to identify the Jenkins instance.