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.

Features:

Dropbear SSH completely runs with SSH version 2 protocol, it never supports SSH version 1. Dropbear is an advanced version of open SSH, it only uses low memory and processor resources. The stunnel program is designed to work as an SSL encryption wrapper between remote client and local (inetd-startable) or remote servers. Dropbear is a relatively small SSH server and client. It runs on a variety of POSIX-based platforms. Dropbear is open source software, distributed under a MIT-style license. Dropbear is particularly useful for 'embedded'-type Linux (or other Unix) systems, such as wireless routers. If you have an OpenSSH-style private key /.ssh/idrsa, you need to do: dropbearconvert openssh dropbear /.ssh/idrsa /.ssh/idrsa.db dbclient -i /.ssh/idrsa.db Dropbear does not support encrypted hostkeys though can connect to ssh-agent. Server: 66.70.190.205: Location: CANADA: Protocol: TCP & UDP: OpenSSH: 22, 255: Dropbear PORT: 80, 8080, 3128, 8888, 143, 111.

• A small memory footprint suitable for memory-constrained environments.
• Dropbear server implements X11 forwarding, and authentication-agent forwarding for OpenSSH clients
• Compatible with OpenSSH ~/.ssh/authorized_keys public key authentication
• The server, client, keygen, and key converter can be compiled into a single binary
• Multi-hop mode uses SSH TCP forwarding to tunnel through multiple SSH hosts in a single command. dbclient user1@hop1,user2@hop2,destination

1. Install

Fedora

CentOS

Install EPEL repo.

Install Dropbear.

Alpine

Debian/Ubuntu/Devuan

Android

Before installing Dropbear on Android you must install Termux, see the video: Termux - emulador de terminal para Android (Spanish)

Install Dropbear.

2. Stop OpenSSH service

Before starting the Dropbear service be sure to stop the sshd service.

systemd based distro: Fedora, CentOS, Debian, Ubuntu

OpenRC based distro: Alpine

sysvinit based distro: Devuan

Android

For Android it is not necessary to stop the SSH service because it is not installed by default.

3. Start Dropbear service

systemd based distro: Fedora, CentOS, Debian, Ubuntu

OpenRC based distro: Alpine

sysvinit based distro: Devuan

Android

We start Dropbear in foreground, by default Dropbear will be listening in port 8022

Dropbear Openssh Key

4. Start the service with the OS

systemd based distro: Fedora, CentOS, Debian, Ubuntu

OpenRC based distro: Alpine

sysvinit based distro: Devuan

Android

It is not advisable to have an SSH server running on Android permanently for security and performance reasons however you can do it by installing Termux:Boot

5. 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. For Android, the recommended way to connect is using public and private keys since you do not have the password for the connecting user (at least in standard mode), for more details see the following video:

Cómo instalar un servidor SSH en Android (Spanish).

For Android you must add the -p 8022 option to the commands: ssh, dbclient.

Using user and password

Using public and private keys

With ssh

To connect to the dropbear server using the ssh client you must use the public and private keys generated by ssh-keygen.

1. Generate public and private keys

2. Copy the public key to the server

3. Connect

With dbclient

To connect to the dropbear server using dbclient you must use public and private keys generated by dropbearkey

2. Copy the public key to the server

3. Connect

Note .ssh DIR must have 700 perms mode and authorized_keys file must have 600 perms mode or you will not be able to connect to the Dropbear server.

Further reading

An SSH server is a software program which uses the secure shell protocol to accept connections from remote computers. SFTP/SCP file transfers and remote terminal connections are popular use cases for an SSH server.

Dropbear Openssl

General[edit]

Platform[edit]

The operating systems or virtual machines the SSH servers are designed to run on without emulation; there are several possibilities:

• No indicates that it does not exist or was never released.
• Partial indicates that while it works, the server lacks important functionality compared to versions for other OSs but may still be under development.
• Beta indicates that while a version is fully functional and has been released, it is still in development (e.g. for stability).
• Yes indicates that it has been officially released in a fully functional, stable version.
• Dropped indicates that while the server works, new versions are no longer being released for the indicated OS; the number in parentheses is the last known stable version which was officially released for that OS.
• Included indicates that the server comes pre-packaged with or has been integrated into the operating system.

The list is not exhaustive, but rather reflects the most common platforms today.

Features[edit]

See also[edit]

Notes[edit]

1. ^Unless otherwise noted, iPhone refers to non-jailbroken devices.
2. ^ ^abOpenSSH and Dropbear are available as optware packages installed by PreWare (maintained by WebOS Internals)
3. ^Lsh supports only one BSD platform officially, FreeBSD.^{[citation needed]}
4. ^Native OpenSSH for Windows 10 is an optional feature that can be installed. OpenSSH can be installed in windows from windows 10 version 1709 and up. The project is called Win32-OpenSSH (contains 64bit as well), hosted on GitHub.
5. ^Most Linux distributions have OpenSSH as an official package, but a few do not.
6. ^OpenSSH 3.4 was the first release included since AIX
7. ^Only for jailbroken devices.
8. ^OpenSSH server can be built with FIPS 140-2

References[edit]

1. ^https://www.bitvise.com/ssh-server-version-history
2. ^'Copssh update - 7.4.0'. itefix.net.
3. ^Changes in Dropbear in official web page
4. ^'Index of /dropbear'. ucc.asn.au.
5. ^'Listing of /~nisse/archive/'. liu.se.
6. ^'OpenSSH 8.4 Release Notes'.
7. ^'Github'.
8. ^'wolfSSH'.
9. ^ ^absshd_config man page on openbsd project 2016-05-18. Retrieved on 2016-05-18.
10. ^OpenSSH 7.5 Release notes, SSHv1 server no longer supported Retrieved on 2017-07-09.