Dropbear is a small and lightweight SSH server and client that can replace OpenSSH on any POSIX platform such as GNU / Linux, * BSD, Cygwin … Dropbear is free software since it is released under MIT-style licenses.
Install EPEL repo.
$ sudo yum -y install epel-release
Stop OpenSSH service
Before starting the Dropbear service be sure to stop the sshd service.
$ sudo bash -c 'systemctl stop sshd && systemctl disable sshd'
Start Dropbear service
$ sudo systemctl start dropbear
Connect to Dropbear server
To connect to the Dropbear server you can use the ssh client (OpenSSH) or the dbclient tool. The dbclient tool is part of the Dropbear package.
Using Openssh client
$ ssh email@example.com
$ dbclient firstname.lastname@example.org