The web config editor is a nodejs application that is running on the localhost:8880 of np04-srv-010.cern.ch, and hence it is not directly accessible from the Internet. To access the web config editor users can either launch a web browser directly on np04-srv-010.cern.ch or port-forward a connection over ssh and launch a web browser locally on their's laptop or desktop. The latter is a preferred option that requires adding the following snippet to the user's local ~/.ssh/config file and ssh-ing into cern-np04-srv-010. The ssh session creates the needed port-forwarding and users can access the web config editor from the localhost.

#replace <your lxplus user account> with your personal user account on lxplus
#add this to your local ~/.ssh/config
Host mylxplushost
  User <your lxplus user account>
  HostName lxplus.cern.ch
  ServerAliveInterval 60
  Protocol 2

Host cern-np04-srv-010
  User pduser
  HostName np04-srv-010.cern.ch
  ProxyCommand ssh -q mylxplushost nc  %h %p
  Protocol 2
  LocalForward 8880 127.0.0.1:8880

Start the port-forwarding by ssh-ing into cern-np04-srv-010.

ssh cern-np04-srv-010

Note: you will be prompted twice to enter a password, the first password to enter is the password for your personal user account on lxplus, and the second password is the password for the pduser user account on np04-srv-010.cern.ch.