This indicates an attempt to connect to a IBM Domino server using Lotus Notes.
IBM Domino and Notes are part of a collaborative software suit which provides business collaboration functions, such as email, calendars, to-do lists, contacts management, chat rooms, discussion forums, file sharing, microblogging, instant messaging, blogs, and user directories. The standard storage mechanism in IBM Domino is a NoSQL document-database format, the "Notes Storage Facility" (.nsf). The .nsf file will normally contain both an application design and its associated data. IBM Notes can also access relational databases, either through an additional server called Lotus Enterprise Integration for Domino, ODBC calls or XPages.