Very nice, here's the plain text version instead of slide format.

Learn to tame OpenBSD quickly.

December 24, 2015

History

Forked from NetBSD. Theo De Raadt is the founder and leader of the OpenBSD project. The first OpenBSD release (1.1/CVS) appear on October 18, 1995.

Why use OpenBSD ?

    UNIX-like
    Get the last version of OpenSSH, OpenSMTPD, OpenNTPD, OpenBGPD, OpenOSPFD, LibreSSL
    Get the last PF (Packet Filter) features
    Security focused Operating System
    Thorough documentation
    Cryptography

Forked from NetBSD. Theo De Raadt is the founder and leader of the OpenBSD project. The first OpenBSD release (1.1/CVS) appear on October 18, 1995.

OpenBSD Version numbers

    Six month release cycle
    New release is incremented by 0.1

OpenBSD's Flavors

    -release: The version of OpenBSD shipped every six months
    -current: Development just after the release
    -stable: Release, plus patches (support ~ 1 year)

Installation

Really simple, ready in 5 minutes (KISS).

Get more information: http://www.openbsd.org/faq/faq4.html

Networking (Files)

  File 	Contain
  /etc/myname 	Default hostname.
  /etc/hostname.if 	Configuration for each network interface, for example: /etc/hostname.bge0
  /etc/mygate 	Default gateway.
  /etc/resolv.conf 	Resolver (DNS).
  /etc/hosts 	Known hosts on the network.

Networking

  # See available network cards:
  /sbin/ifconfig
  
  # Restart networking service:
  /bin/sh /etc/netstart
  
  # Set DHCP for 're0' interface, on the fly:
  /sbin/dhclient re0

Networking (Routing)

  # Show the routing table (ipv4):
  /usr/bin/netstat -rnf inet
  
  # Show the routing table (ipv6):
  /usr/bin/netstat -rnf inet6
  
  # Delete all gateway entries from the routing table:
  /sbin/route -n flush

Networking (set at startup)

Example 1: configure static IP address for re0.

  ## file: /etc/hostname.re0
  inet 192.168.0.58 255.255.255.0
  
  # For more information, read the manual: hostname.if(5)

Don't forget to run 'sh /etc/netstart re0' to apply changes to running system.

Example 2: configure DHCP for bge0.

  ## file: /etc/hostname.bge0
  dhcp
  
  # For more information, read the manual: hostname.if(5)

Don't forget to run 'sh /etc/netstart bge0' to apply changes to running system.

Example 3: configure wireless.

  ## file: /etc/hostname.iwn0
  nwid ACCESS_POINT_NAME
  wpakey THE_SECRET_KEY
  dhcp
  
  # For more information, read the manual: hostname.if(5)

Don't forget to run 'sh /etc/netstart iwn0' to apply changes to running system.

PF (Packet Filter)

  Ruleset: /etc/pf.conf

Useful commands.

  # Disable PF
  /sbin/pfctl -d
  
  # Enable PF and load the rules
  /sbin/pfctl -ef /etc/pf.conf
  
  # Just load the rules (apply changes)
  /sbin/pfctl -f /etc/pf.conf
  
  # View the loaded rules
  /sbin/pfctl -s rules

For more information, read the manual: pfctl(8)

Pf ruleset sample

  ## file: /etc/pf.conf
  # Protect a laptop (allow only ping/ssh from anywhere)
  set skip on lo
  set fingerprints "/dev/null"
  block log all
  pass in on egress inet proto icmp all icmp-type echoreq
  pass in on egress inet proto tcp from any to any port ssh
  pass out
  
  # For more information, read the manual: pf.conf(5)

Debug PF with tcpdump(8)

  /usr/sbin/tcpdump -nettti pflog0

Manage users

Manually

  /usr/sbin/user [add|del|info|mod] user_name

The interactive way

  # Add users
  /usr/sbin/adduser  
  
  # Remove users
  /usr/sbin/rmuser

For more information, read the manual: adduser(8)

Manage Groups

  File: /etc/group  
  
  /usr/sbin/group [add|del|info|mod] group_name

Members in 'wheel' group can use su(1) to become 'root'.

For more information, read the manual: group(8,5)

sudo replaced with doas(1)

  ## file: /etc/doas.conf
  # Permit the user 'Marc' to reboot the box
  permit nopass marc as root cmd reboot

Marc can now reboot the box:

  $ doas reboot

For more information, read the manual: doas.conf(5)

Install Packages

  export PKG_PATH=http://ftp.openbsd.org/pub/OpenBSD/5.8/packages/amd64/
  
  # OR use 'installpath' variable in /etc/pkg.conf:
 installpath=http://ftp2.fr.openbsd.org/pub/OpenBSD/%c/packages/%a/

  # Add sudo package
  /usr/sbin/pkg_add sudo

Some packages provide configuration and other information in a file located in '/usr/local/share/doc/pkg-readmes'.

For more information, read the manual: pkg.conf(5)

Packages

  # List packages installed
  /usr/sbin/pkg_info
  
  # View install-message for a specific package
  /usr/sbin/pkg_info -M package_name
  
  # Remove a Package
  /usr/sbin/pkg_delete package_name
  
  # Delete unused dependencies 
  /usr/sbin/pkg_delete -a

For more information, read the manual: packages(7)

Install non-free firmware packages

  /usr/sbin/fw_update

Firmware is downloaded from release-specific directories at: http://firmware.openbsd.org/firmware/

Manage daemons, services

  File: /etc/rc.conf.local
  
  /usr/sbin/rcctl [enable|disable|start|stop|reload|restart] daemon_name
  
  # Examples
  /usr/sbin/rcctl enable ipsec
  /usr/sbin/rcctl enable isakmpd
  /usr/sbin/rcctl set isakmpd flags -K
  /usr/sbin/rcctl start isakmpd

For more information, read the manual: rcctl(8)

Run a script at startup

  File: /etc/rc.local

For more information, read the manual: rc.local(8)

Update OpenBSD

Any security or reliability fixes can be found at: http://www.openbsd.org/errata.html

You can also use the openup tool from M:tier

Upgrade OpenBSD

To upgrade 5.6 to 5.8, you need to follow instructions:

http://www.openbsd.org/faq/upgrade57.html & http://www.openbsd.org/faq/upgrade58.html

OpenBSD Filesystem

  The most important:
  / 	Root directory.
  /home 	User home directories.
  /root 	Default home directory for the superuser.
  /mnt 	A temporary mount point.
  /etc 	System configuration files and scripts.
  /etc/examples 	Example configuration files for base system daemons.
  /etc/skel 	(dot) files for new accounts.
  /etc/signify 	Key files used for signify(1).
  /tmp 	Cleaned after a reboot.
  /var/tmp 	Symbolic link to the system /tmp.
  /var/log 	Log files.
  /var/run 	pid, socket files, utmp, dmesg.boot
  /var/db 	Database files.
  /var/www 	Configuration files for httpd(8).
  /usr/local 	Used for third packages installed.
  /usr/src 	BSD and/or local source files.

For more information, read the manual: hier(7)

OpenBSD Kernels

  /bsd
  Pure kernel executable (the operating system loaded into memory at boot-time).
  /bsd.mp
  Pure kernel executable for multiprocessor machines.
  /bsd.rd
  Installation kernel. The built-in RAM disk contains utilities which can be run without an external file system, so this kernel is useful for limited system maintenance too.

Tune the system

  sysctl(8) get or set kernel state
  config(8) modify a kernel

Need more help ?

  FAQ: http://www.openbsd.org/faq/
  Manual page: afterboot(8)
  Mailing list: misc@

Presentations & Papers

  http://www.openbsd.org/papers/

Supporting OpenBSD

  Donations [1]
  
  OpenBSD Foundation [2]
  
  OpenBSD Store [3]

Thank you. Feedback: contact@

[1] http://www.openbsd.org/donations.html

[2] http://www.openbsdfoundation.org/

[3] http://www.openbsdstore.com/