OpenBSD FAQ - Introduction to OpenBSD [FAQ Index]

About 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 portability.

Why might I want to use it?

Some reasons why we think OpenBSD is a useful operating system:

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. More about OpenBSD's copyright policy can be found here.

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, 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.

What's included in the base system?

OpenBSD is distributed with a number of third-party software products, including: The OpenBSD team often patches third party products, typically to improve the security or quality of the code. Much home-grown software is also included. Additional applications are available as packages.

Why is/isn't ProductX included?

People often ask why a particular product is or isn't included with OpenBSD. The answer is based on two things: the wishes of the developers and compatibility with the goals of the project. Licensing is often the biggest problem: we want OpenBSD to remain usable by any person anywhere in the world for any purpose.

When is the next release?

The OpenBSD team makes a new release approximately every six months, with the target release dates in May and November. More information on the development cycle can be found here.

Hardware Support

OpenBSD runs on the following platforms: Specific hardware support details are on the respective platform pages.

Manual Pages

OpenBSD comes with extensive documentation in the form of man pages. They are the authoritative source of information for OpenBSD, and considerable effort is made to ensure they're up to date and accurate. Developers making a change to the system are expected to update the man pages along with their change to the system code. It is expected that users will check the man pages before asking for help.

Here is a list of some useful manual pages for new users:

All of the OpenBSD man pages can be found on the web at as well as in the man75.tgz file set.

In general, if you know the name of a command or a manual page, you can read it by executing man command. If you don't know the name of the command, or if man command doesn't find the manual page, you can search the manual page database by executing apropos something or man -k something, where something is a likely word that might appear in the title of the manual page you're looking for.

$ apropos "time zone"
tzfile(5) - time zone information
zdump(8) - time zone dumper
zic(8) - time zone compiler
The parenthetical numbers indicate the section of the manual in which that page can be found. In some cases, you may find manual pages with identical names living in separate sections of the manual. For example, assume that you want to know the format of the configuration files for the cron daemon. Once you know the section of the manual for the page you want, you would execute man n command, where n is the manual section number.
$ man -k cron
cron(8) - clock daemon
crontab(1) - maintain crontab files for individual users
crontab(5) - tables for driving cron
$ man 5 crontab

Mailing Lists

The OpenBSD project maintains several mailing lists that users can subscribe to and follow. Some of the more popular lists are: Before posting a question on any mailing list, please check the archives for most common questions have been asked repeatedly. While it might be the first time you have encountered the problem or question, others on the mailing lists may have seen the same question several times in the last week, and may not appreciate seeing it again. If asking a question possibly related to hardware, always include a full dmesg(8).

You can find several archives, other guidelines and more information on the mailing list page. Subscriptions can be easily managed via the web interface.

Migrating to OpenBSD

If you learned Unix from any of the good books on general Unix, understanding the Unix philosophy and then extending your knowledge to a particular platform, you will find OpenBSD to be familiar.

Here are some of the commonly encountered differences between OpenBSD and other Unix variants.

Reporting Bugs

Reporting bugs is one of the most important responsibilities of end users. Very detailed information is required to diagnose most serious issues. For example, the following would be an appropriate bug report:
Subject: 3.3-beta panics on a SPARCStation2

OpenBSD 3.2 installed from an official CD-ROM installed and ran fine
on this machine.

After doing a clean install of 3.3-beta from a mirror, I find the
system randomly panics after a period of use, and predictably and
quickly when starting X.

This is the dmesg output:


This is the panic I got when attempting to start X:

panic: pool_get(mclpl): free list modified: magic=78746572; page 0xfaa93000;
 item addr 0xfaa93000
Stopped at      Debugger+0x4:   jmpl            [%o7 + 0x8], %g0 describes the minimum info required in bug
reports. Insufficient info makes it difficult to find and fix bugs.
ddb> trace

Thank you!
See this page for more information on creating and submitting bug reports. Include detailed information about what happened, the exact configuration of your system, and how to reproduce the problem. Please use sendbug(1) to report your problems whenever possible. Otherwise, please include at least the dmesg(8) output of your system. The sendbug(1) command requires that your system be able to send email.

The OpenBSD mail server uses spamd(8) for greylisting, so it may take half an hour or so before the mail server accepts your bug report. Please be patient.

After submitting a bug report, you may be contacted by developers for additional information or with patches that need testing. You can also monitor the archives of the mailing list - details on the mailing list page.

Supporting the Project

We are greatly indebted to the people and organizations that have contributed to the OpenBSD project.

OpenBSD has a constant need for several types of support from the community. If you find OpenBSD useful, you are strongly encouraged to find a way to contribute.