The groupware server

HCLs (former IBMs) groupware package offers a built in web server.
The server component is commonly refered to as Lotus Domino.
This part of the software communicates with your installed

  1. IBM Notes Client using the NRPC protocol over tcp port 1352 and/or
  2. Web browser using the http protocol over tcp port 80 or the secure 443

A common use these days is to have your mobile device (iPhone, iPad, Android) connected to the server part.
The server task running on the Domino server is called Traveller.