Opensshenum is an user enumerator permitting to verify a list of user names to know those actually configured on a server using OpenSsh. This program  exploits a bug ( corrected in July 2018  ) proven to be effective at least starting from OpenSSH 2.3.0 ( released in November 2000). It also provides a ssh port scanner, to individuate ssh daemons listening on non-standard ports. A simple Gnu Parallel script ( parallenum.sh  ) is provided to reduce drastically the scanning time, where it's possible.