To do this for dropbear is quite simple, on Debian/Ubuntu based systems:
Head to
/etc/default/dropbear:
You may have a quite a few lines or you may have little, this just depends on how it was installed.
# disabled because OpenSSH is installed
# change to NO_START=0 to enable Dropbear
NO_START=0
# the TCP port that Dropbear listens on
DROPBEAR_PORT=51096
# any additional arguments for Dropbear
DROPBEAR_EXTRA_ARGS=-g
As seen above, you will want to have DROPBEAR_PORT=51096 on a line to change the default dropbear port.
To disable root password login, root logins, etc. you will need to have DROPBEAR_EXTRA_ARGS=xxxxx on another line.
-g = Disable password logins for root
-s = Disable password logins
-w = Disable root logins
An example would be
DROPBEAR_EXTRA_ARGS=-s to disable password logins on all accounts including root.
Finally you will want to
service dropbear restart or
/etc/init.d/dropbear restart to finalize the changes.
This is taken from my other post. Just thought it would help some others.