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1 - Introduction to OpenBSD
Table of Contents
1.1 - What is OpenBSD?
The OpenBSD project produces a freely
available, multi-platform 4.4BSD-based UNIX-like operating system. Our
goals place emphasis on correctness,
security, standardization, and
This FAQ specifically covers only the most recent release of
OpenBSD, version 5.3.
1.2 - On what systems does OpenBSD run?
OpenBSD 5.3 runs on the following platforms:
Available on CD means the official CD
set includes that platform and a number of
Base system CD ISO images can also be downloaded for most other
These images are not the same as the official CD sets.
More information on OpenBSD platforms can be found on the
People sometimes ask why we support so many "odd" machines.
The short answer is, "because we want to".
If enough skilled people (sometimes, "enough" is only one really skilled
person!) wish to maintain support for a platform, it will be
There are practical benefits to keeping OpenBSD multi-platform: when new
platforms come out, the code tree is relatively free of
portability-breaking bugs and design flaws.
The OpenBSD platforms include 32 bit and 64 bit processors, little and
big endian machines, and many different designs.
And yes, supporting "unusual" platforms has helped produced a
higher-quality code base for more "common" platforms.
1.3 - Why might I want to use OpenBSD?
New users frequently want to know whether OpenBSD is superior to some
other free UNIX-like operating system. That question is largely
unanswerable and is the subject of countless (and useless) religious
debates. Do not, under any circumstances, ask such a question on an
OpenBSD mailing list.
Below are some reasons why we think OpenBSD is a useful operating
- OpenBSD runs on many different hardware
- OpenBSD is thought of by many security professionals as the
most secure UNIX-like operating system,
as the result of a never-ending comprehensive source code
- OpenBSD is a full-featured UNIX-like operating system available
in source form at no charge.
- OpenBSD integrates cutting-edge security technology suitable for
building firewalls and private
network services in a distributed environment.
- OpenBSD benefits from strong ongoing development in many areas,
offering opportunities to work with emerging technologies with an
international community of programmers and end-users.
- OpenBSD attempts to minimize the need for customization and
For the vast majority of users, OpenBSD "Just Works" on their
hardware for their application.
Not only is tweaking and customizing rarely needed, it is actively
However, whether OpenBSD is right for you is a question that only you
1.4 - Is OpenBSD really free?
OpenBSD is all free. The binaries are free. The source is free. All
parts of OpenBSD have reasonable copyright terms permitting free
redistribution. This includes the ability to REUSE most parts of the
OpenBSD source tree, either for personal or commercial purposes. OpenBSD
includes NO further restrictions other than those implied by the
original BSD license. Software which is written under stricter licenses
cannot be included in the regular distribution of OpenBSD. This is
intended to safeguard the free use of OpenBSD. For example, OpenBSD can
be freely used for personal use, for academic use, by government
institutions, by non-profit making organizations and by commercial
OpenBSD, or parts of it, can also be freely incorporated into
People sometimes ask if it bothers us that our free work is put into
The answer is, we would prefer that our good code be widely used
rather than have commercial software vendors reimplement and create badly
coded or incompatible alternative solutions to already solved problems.
For example, it is likely that SSH is a widely used protocol due to
this freedom, much more widely used than if restrictions had been placed
on how people used the OpenSSH code. If a free SSH solution was not
available for vendors to use (in their multitude of rapidly developed
products), they would have written or purchased some crummy off-the
shelf version instead.
This isn't to say we would object to financial
or hardware support in thanks.
In fact, it is stunning how little support of any kind comes from
companies that depend upon OpenBSD (or OpenSSH) for their products, but
there is no requirement of compensation.
For further reading on other popular licenses read:
OpenBSD Copyright Policy.
The maintainers of OpenBSD support the project largely from their own
pockets. This includes the time spent programming for the project,
equipment used to support the many ports, the network resources used to
distribute OpenBSD to you, and the time spent answering questions and
investigating users' bug reports. The OpenBSD developers are not
independently wealthy and even small contributions of time, equipment,
and resources make a big difference.
1.5 - How can I help support OpenBSD?
We are greatly indebted to the people and organizations that have
contributed to the OpenBSD project. They are acknowledged by name
on the donations page.
OpenBSD has a constant need for several types of support from the user
community. If you find OpenBSD useful, you are strongly encouraged to
find a way to contribute. If none of the suggestions below are right for
you, feel free to propose an alternative by sending e-mail to
- Buy an OpenBSD CD set. It includes
the current full release of OpenBSD, and is bootable on many
platforms. It also generates revenue to support the OpenBSD project,
and reduces the strain on network resources used to deliver the
distribution via the Internet. This inexpensive three-CD set
includes full source. Remember, your friends need their own copy!
- Donate money. The project has a
constant need for cash to pay for equipment, network connectivity,
and expenses relating to CD publishing. Manufacturing CDs requires
an up-front out-of-pocket investment for the OpenBSD developers,
without guaranteed return. Send e-mail to
find out how to contribute. Even small donations make a profound
- Donate equipment and parts. The
project has a constant need for general and specific hardware. Items
such as IDE, SCSI, SATA and SAS disks, and various types of RAM are always
welcome. For other types of hardware such as computer systems and
motherboards, you should inquire as to current need. Write to
arrange for shipment.
- Donate your time and skills. Programmers who enjoy writing
operating systems are naturally always welcome, but there are
literally dozens of other ways that people can be useful. Follow
mailing lists and help answer new-user
- Help maintain documentation by submitting new FAQ material (to
firstname.lastname@example.org). Form a local
user group and get your friends hooked
on OpenBSD. Make a case to your employer for using OpenBSD at work.
If you're a student, talk to your professors about using OpenBSD as
a learning tool for Computer Science or Engineering courses. It's
also worth mentioning one of the most important ways you should not
try to "help" the OpenBSD project: do not waste your time engaging
in operating system flame wars. It does not help the project to find
new users and can cause substantial harm to important relationships
that developers have with other developers.
1.6 - Who maintains OpenBSD?
OpenBSD is maintained by a development team spread across many different
countries. The project is coordinated by
Theo de Raadt, located in Canada.
1.7 - When is the next release of OpenBSD?
The OpenBSD team makes a new release every six months, with target release
dates in May and November. More information on the development cycle
can be found here.
1.8 - What is included with OpenBSD?
OpenBSD is distributed with a number of third-party software products,
As can be seen, the OpenBSD team often patches third-party products
(typically) to improve the security or quality of the code. In
some cases, the user will see no difference in operation, in other
cases, there ARE operational differences which may impact some users.
Keep these enhancements in mind before blindly adding different versions
of the same software.
You may get a bigger version number, but a less secure system.
- X.org 7.7,
the X Window environment, with local patches.
Installed with the x*.tgz
install file sets.
- GCC versions 4.2.1, 3.3.6 or
2.95.3 (depending on your platform) GNU C Compiler.
Installed as part of the comp53.tgz
- Perl 5.12.2, with patches and
improvements from the OpenBSD team.
- Our improved and secured version of the Apache 1.3 web server.
The OpenBSD team has added default
chrooting, privilege revocation, and other security-related
improvements. Also includes mod_ssl and DSO support.
- Nginx 1.2.6 web server, with
- OpenSSL 1.0.1c, with patches
and improvements from the OpenBSD team.
- SQLite 220.127.116.11, with patches
and improvements from the OpenBSD team.
- Sendmail 8.14.6 mail
server, with libmilter.
- BIND 9.4.2-P2
(plus patches) DNS server.
OpenBSD has implemented many improvements in chroot operation
and other security-related issues.
- NSD 3.2.15
authoritative DNS server.
- Lynx 2.8.7rel.2 text web browser.
With HTTPS and IPv6 support added, plus patches from the OpenBSD team.
- Sudo v1.7.2p8, allowing
users to run individual commands as root.
- Heimdal 0.7.2 with patches.
- Arla 0.35.7
- Binutils 2.15
- gdb 6.3 with
- OpenSSH 6.2
- OpenSMTPD Secure, simple and
reliable Mail Transport Agent (MTA).
- OpenNTPD Secure and simple
Network Time Protocol implementation.
- OpenBGPD and OpenOSPFD
Of course, additional applications can be added through the OpenBSD
packages and ports system.
1.9 - What is new in OpenBSD 5.3?
The complete list of changes made to OpenBSD 5.2 to create OpenBSD 5.3
can be found on plus53.html, and highlights
on the OpenBSD 5.3 Information page, however
here are a few changes the OpenBSD team anticipate will require or
warrant some special note to people upgrading or installing OpenBSD 5.3
who are familiar with older versions:
- OpenSMTPD is ready for
New installations should consider using OpenSMTPD as their mail
Existing installs should look at using OpenSMTPD to replace sendmail,
as at some point in the future, sendmail will probably be removed.
dhclient-script elimintated, HUP signals cause the client to reread the
configuration files and obtain a new lease, killing dhclient will
attempt to remove routes and addresses it had configured, and lots of
- Improved hardware support:
The usual improvements to support new and old hardware, including
network interfaces and disk interfaces.
1.10 - Can I use OpenBSD as a desktop system?
This question is often asked in exactly this manner -- with no
explanation of what the asker means by "desktop".
The only person who can answer that question is you, as it depends on
what your needs and expectations are.
While OpenBSD has a great reputation as a "server" operating system, it
can be and is used on the desktop.
Many "desktop" applications are available through
packages and ports.
As with all operating system decisions, the question is: can it do the
job you desire in the way you wish?
You must answer this question for yourself.
It might be worth noting that a large amount of OpenBSD development is
done on laptops.
1.11 - Why is/isn't ProductX included?
People often ask why a particular product is or isn't included with
The answer is based on two things: the wishes of the developers and
compatibility with the goals of the
A product will not be included simply because it is "nifty" -- it must
also be "free" for use, distribution and modification by our standards.
A product must also be stable and secure -- a bigger version number does
not always mean a better product.
License is often the biggest problem: we want OpenBSD to remain usable
by any person anywhere in the world for any purpose.
Another major consideration is the wishes of the developers.
The OpenBSD developers are the ultimate judges of what does and doesn't
go into the project.
Just because an application is "good" doesn't mean the OpenBSD project
wishes to devote the resources needed to maintaining it, or that
they will share other's enthusiasm about its place in OpenBSD.
Some commonly asked questions about third-party products:
In most cases, these topics have been discussed in painful detail on
the mail lists, please see archives
if you need more information.
- Why isn't Postfix included?
The license is not free, and thus
can not be considered.
- Why isn't qmail or djbdns included?
Neither program is what many Unix users "expect" out of a mail or
- Why is Apache included? It isn't needed by many people!
Because the developers want it.
- Why isn't a newer version of Apache included?
The license on newer versions is unacceptable.
Users interested in more modern web servers are encouraged to look at
which will hopefully be replacing Apache in base.
- Why isn't bzip2 included instead of gzip?
Performance is horrible, and benefit is minimal.
Impact on slower platforms, such as hp300 or VAX would be unacceptable.
- Why isn't there a graphical or
For a number of reasons, including the goal of keeping the installation
boot media able to be a single floppy disk, the fact that one installer
can be used on all platforms in all configurations, and the fact that
after the second or third OpenBSD install, most users find the OpenBSD
installation system among the fastest and easiest installers of any OS.
Most developers and users greatly prefer the speed, power, and ease of
use of the current installer to any of the more "colorful" or "pretty"
installers on some other platforms.
- Will ZFS be added to OpenBSD?
Not unless someone can convince Oracle to change the license for it to
something compatible with OpenBSD policy.
Of course, if you wish to use one of these packages and your use is
compatible with the license of the products, no one will stop you (that
wouldn't be very free if we tried, would it?).
However, your needs may change -- you may not want to develop a
"Killer Application" that you can't sell, distribute, or get rich from
because you incorporated non-free software into it.
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