Change JENKINS-44166 of the Jenkins P4 plugin modified the plugin to work in cases when a pre-login perforce triggers was being used.

The 'fix' for the above issue:

• https://github.com/jenkinsci/p4-plugin/commit/ecbf8628e4f7104f73ab329b9b81065bc19fc44d

now means that a 'p4 login -s' call is made to the Perforce server during each and every call to the isLogin() method. This can literally result in 10,000's of 'p4 login -s' requests an hour and cause the server to lock up (by using up all the available TCP sockets).

The consequence being very similar to a DoS attach on the Perforce server.