Name: Absolute OpenBSD
ISBN: 9781886411999

Absolute OpenBSD

OpenBSD, the elegant, highly secure Unix-like operating system, is widely used as the basis for critical DNS servers, routers, firewalls, and more. This long-awaited second edition of Absolute OpenBSD maintains author Michael Lucas's trademark straightforward and practical approach that readers have enjoyed for years. You'll learn the intricacies of the platform, the technical details behind certain design decisions, and best practices, with bits of humor sprinkled throughout. This edition has been completely updated for OpenBSD 5.3, including new coverage of OpenBSD's boot system, security features like W^X and ProPolice, and advanced networking techniques. You'll learn how to: –Manage network traffic with VLANs, trunks, IPv6, and the PF packet filter –Make software management quick and effective using the ports and packages system –Give users only the access they need with groups, sudo, and chroots –Configure OpenBSD's secure implementations of SNMP, DHCP, NTP, hardware sensors, and more –Customize the installation and upgrade processes for your network and hardware, or build a custom OpenBSD release Whether you're a new user looking for a complete introduction to OpenBSD or an experienced sysadmin looking for a refresher, Absolute OpenBSD, 2nd Edition will give you everything you need to master the intricacies of the world's most secure operating system.

What Hacker News says

skydhashAug 2026

I’m using OpenBSD as a daily desktop. The main motivation is that it’s a complete system instead of several projects. So you got simpler userland tools as the kernel interfaces can be easily adjusted.

Also the subsystems are way simpler (packet filtering, sound, network management). Linux is full choke of abstraction which aim to serve a huge range of devices. And I truly believe that there should have been a bifurcation somewhere.

Most software are easy to port around, but there are some that relies on linuxisms (udev) and some on glibc-isms, which can require some patching. Some of the pains I encountered are about device files (usb) and the fact that openbsd relies on root a bit more (mounting with fuse).

You can read the “Absolute OpenBSD, 2ed” book, published 13 years ago and almost everything still holds. You can even read the “Design and Implementation of the 4.4BSD” and still have a good understanding of the OpenBSD design. Linux is chaotic land compared to that.

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SoftTalkerAug 2026

For BSD (especially OpenBSD) you can pretty much just use the man pages and the online FAQ. They are really good.

If you want a book, Absolute OpenBSD is good though a bit out of date now. A lot of it would still be applicable though, if backed up by the current man pages.

Reading undeadly.org is a another good way to keep up on developments.

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nelsonicMay 2026

How long did what take? Learning the essentials of OpenBSD, budget 4-6hours. Switching over servers from Ubuntu, an hour for the first one then 10mins each after that. You can copy config with your favourite tools; most have ports for OpenBSD already. If you want to learn more in-depth, read: Michael W. Lucas Absolute OpenBSD, 2nd Edition: Unix for the Practical Paranoid. Highly recommend it as teaches many fundamentals most software engineers skip.

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b3lm0ntOct 2023

Seconded. Nice, concise volume that helped me setup hosting for multiple sites on a single VM with different requirements (some reverse proxy, some CGI, some static).

Really looking forward to the 3rd edition of Absolute OpenBSD.

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ninjinDec 2022

Michael is indeed a gem and I am happy to hear that his writing is equally strong on the FreeBSD side of things. Absolute OpenBSD was my introduction to OpenBSD in the mid-00s and I just recently re-read the latest edition (a new one is rumoured to be in the works) now that I am looking to go back to OpenBSD. Yes, you can absolutely just go with the manuals and FAQ with the amount of Unix-like experience I have at this point, but Michael frequently notes clever tricks and confers the different mentality on things that exists in the OpenBSD community. This, in short, is priceless.

I have worked through Httpd and Relayd Mastery as well and I am eyeing up SNMP Mastery, Ed Mastery (I expect Michael to make me laugh a good few times), and SSH Mastery after I am done with OpenBSD Mastery: Filesystems and (not by Michael though) The book of PF. Keeping Michael fed seems like a great way to bring more BSD knowledge out there and hopefully keep an alternative to the now so very corporate (and much larger) Linux sphere going.

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ninjinSep 2022

“Linux” indeed… I know for a fact that Absolute OpenBSD, The Book of PF, and Designing BSD Rootkits are great. Tempted to pick up the bundle to read FreeBSD Device Drivers, The Book of GIMP, Absolute FreeBSD, and The Book of Inkscape.

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