Dropbear SSH

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 want to be notified of new releases, or for general discussion of Dropbear, you can subscribe to the relatively low volume mailing list.

Features

• A small memory footprint suitable for memory-constrained environments – Dropbear can compile to a 110kB statically linked binary with uClibc on x86 (only minimal options selected)
• Dropbear server implements X11 forwarding, and authentication-agent forwarding for OpenSSH clients
• Can run from inetd or standalone
• Compatible with OpenSSH ~/.ssh/authorized_keys public key authentication
• The server, client, keygen, and key converter can be compiled into a single binary (like busybox)
• Features can easily be disabled when compiling to save space
• Multi-hop mode uses SSH TCP forwarding to tunnel through multiple SSH hosts in a single command. dbclient [email protected],[email protected],destination

Platforms

• Linux – standard distributions, uClibc >=0.9.17, dietlibc, musl libc, uClinux from inetd
• Mac OS X (compile with PAM support)
• FreeBSD, NetBSD and OpenBSD
• Solaris – tested v8 x86 and v9 Sparc
• IRIX 6.5 (with /dev/urandom, or prngd should work)
• Tru64 5.1 (using prngd for entropy)
• AIX 4.3.3 (with gcc and Linux Affinity Toolkit), AIX 5.2 (with /dev/urandom).
• HPUX 11.00 (+prngd), TCP forwarding doesn't work
• Cygwin – tested 1.5.19 on Windows XP

It shouldn't be hard to get it to work on other POSIX platforms, it is mostly a case of setting up the configure and Makefile settings.

Acknowledgements

The cryptographic code utilises Tom St Denis's LibTomCrypt, and uses his LibTomMath library for the bignum parts. PTY handling code is taken from OpenSSH (from Tatu Ylönen's original ssh), login recording (utmp/wtmp) code is from OpenSSH by Andre Lucas, and some implementation details were gleaned from PuTTY. Numerous people have contributed patches and bug reports, see CHANGES. Particular thanks go to Mihnea Stoenescu for his work on the client portion.

Dropbear's website is hosted by The University Computer Club in Perth, Australia

My email address is matt@ucc.asn.au
Matt Johnston

Up to Homepage