OpenBSD F.A.Q March 2012 2 Contents 1 Introduction to OpenBSD 13 1.1 What is OpenBSD? . 14 1.2 On what systems does OpenBSD run? . 14 1.3 Why might I want to use OpenBSD? . 15 1.4 Is OpenBSD really free? . 15 1.5 How can I help support OpenBSD? . 16 1.6 Who maintains OpenBSD? . 17 1.7 When is the next release of OpenBSD? . 17 1.8 What is included with OpenBSD? . 17 1.9 What is new in OpenBSD 5.0? . 19 1.10 Can I use OpenBSD as a desktop system? . 19 1.11 Why is/isn't ProductX included? . 19 2 Getting to know OpenBSD 23 2.1 Web Pages of Interest . 24 2.2 Mailing Lists . 24 2.3 Manual Pages . 25 2.4 Reporting Bugs . 29 3 Getting started with OpenBSD 37 3.1 Buying an OpenBSD CD set . 38 3.2 Buying OpenBSD T-Shirts . 38 3.3 Does OpenBSD provide an ISO image for download? . 38 3.4 Downloading via HTTP, FTP or AFS . 39 3.5 Selecting Hardware . 39 3.6 What is an appropriate ”first system" to learn OpenBSD on? . 41 4 OpenBSD 4.9 Installation Guide 43 4.1 Overview of the OpenBSD installation procedure . 44 4.2 Pre-installation checklist . 46 4.3 Creating bootable OpenBSD install media . 46 4.3.1 Making a CD-ROM . 47 4.3.2 Creating floppies on Unix . 48 4.3.3 Creating floppies on Windows . 48 3 4 CONTENTS 4.4 Booting OpenBSD install media . 49 4.5 Performing a simple install . 49 4.5.1 Starting the install . 49 4.5.2 The Install Questions . 51 4.5.3 Setting up disks . 54 4.5.4 Choosing installation media and file sets . 56 4.5.5 First boot! . 58 4.5.6 One last thing... 58 4.6 Details for a more complex install . 59 4.6.1 Setting up the network . 59 4.6.2 Setting the Time Zone . 60 4.6.3 Custom fdisk(8) layout . 61 4.6.4 Custom disklabel layout . 66 4.7 What files are needed for installation? . 71 4.8 How should I partition my disk? . 73 4.9 Multibooting OpenBSD (amd64, i386) . 77 4.10 Sending your dmesg to [email protected] after the install . 80 4.11 Adding a file set after install . 82 4.12 What is 'bsd.rd'? .......................... 82 4.13 Common installation problems . 83 4.13.1 My Compaq only recognizes 16M RAM . 83 4.13.2 My i386 won't boot after install . 83 4.13.3 My (older, slower) machine booted, but hung at the ssh-keygen steps . 84 4.13.4 I got the message "Failed to change directory" when doing an install . 84 4.13.5 My fdisk partition table is trashed or blank! . 85 4.13.6 I have no floppy or CD-ROM on my machine . 85 4.13.7 I got an SHA256 mismatch during install! . 86 4.14 Customizing the install process . 86 4.15 How can I install a number of similar systems? . 87 4.16 How can I get a dmesg(8) to report an install problem? . 88 5 Building the System from Source 91 5.1 OpenBSD's Flavors . 92 5.2 Why do I need to compile the system from source? . 95 5.3 Building OpenBSD from source . 95 5.3.1 Overview of the building process . 95 5.3.2 Install or Upgrade to closest available binary . 96 5.3.3 Fetching the appropriate source code . 96 5.3.4 Building the kernel . 99 5.3.5 Building the userland . 100 5.4 Building a Release . 101 5.5 Building X (Xenocara) . 102 5.6 Why do I need a custom kernel? . 103 5.7 Building a custom kernel . 105 CONTENTS 5 5.8 Boot-Time Configuration . 107 5.9 Using config(8) to change your kernel . 108 5.10 Getting more verbose output during boot . 110 5.11 Common problems, tips and questions when compiling and building110 5.11.1 The build stopped with a "Signal 11" error . 111 5.11.2 "make build" fails with "cannot open output file snake: is a directory" . 111 5.11.3 My IPv6-less system doesn't work! . 111 5.11.4 Oops! I forgot to make the /usr/obj directory first! . 111 5.11.5 Tip: Put /usr/obj on its own partition . 112 5.11.6 How do I not build parts of the tree? . 112 5.11.7 Where can I learn more about the build process? . 112 5.11.8 I didn't see any snapshots on the FTP site. Where did they go? . 112 5.11.9 How do I bootstrap a newer version of the compiler (gcc)? 113 5.11.10 What is the best way to update /etc, /var, and /dev? . 113 5.11.11 Is there an easy way to make all the file hierarchy changes?114 5.11.12 Can I cross-compile? Why not? . 114 6 Networking 115 6.1 Before we go any further . 116 6.2 Network configuration . 116 6.2.1 Identifying and setting up your network interfaces . 116 6.2.2 Default gateway . 119 6.2.3 DNS Resolution . 119 6.2.4 Host name . 119 6.2.5 Activating the changes . 119 6.2.6 Checking routes . 120 6.2.7 Setting up your OpenBSD box as a forwarding gateway . 121 6.2.8 Setting up aliases on an interface . 121 6.3 How do I filter and firewall with OpenBSD? . 122 6.4 Dynamic Host Configuration Protocol (DHCP) . 123 6.4.1 DHCP Client . 123 6.4.2 DHCP Server . 124 6.5 PPP . 125 6.6 Tuning networking parameters . 128 6.6.1 I don't want the kernel to dynamically allocate a certain port . 129 6.7 Simple NFS usage . 129 6.8 Setting up a network bridge in OpenBSD . 132 6.9 How do I boot using PXE? (i386, amd64) . 135 6.10 The Common Address Redundancy Protocol (CARP) . 137 6.10.1 What is CARP and how does it work? . 137 6.10.2 Configuration . 138 6.10.3 Load balancing . 140 6.10.4 More Information on CARP . 140 6 CONTENTS 6.11 Using OpenNTPD . 141 6.11.1 "But OpenNTPD isn't as accurate as the ntp.org daemon!"141 6.11.2 "Someone has claimed that OpenNTPD is 'harmful'!" . 141 6.11.3 Why can't my other machines synchronize to OpenNTPD?142 6.12 What are my wireless networking options? . 142 7 Keyboard and Display Controls 145 7.1 How do I remap the keyboard? (wscons) . 146 7.2 Is there console mouse support in OpenBSD? . 146 7.3 Accessing the Console Scrollback Buffer (amd64, i386, some Alpha)146 7.4 How do I switch consoles? (amd64, i386, Zaurus, some Alpha) . 146 7.5 How do I use a console resolution of 80x50? (amd64, i386, some Alpha).................................147 7.6 How do I use a serial console? . 148 7.7 How do I blank my console? (wscons) . 152 7.8 EVERYTHING I TYPE AT THE LOGIN PROMPT IS IN CAPS!152 7.9 What is tmux? . 153 7.9.1 Advanced tmux usage . 157 8 General Questions 159 8.1 X won't start, I get lots of error messages . 161 8.2 Can I use programming language "L" on OpenBSD? . 161 8.3 What is the ports tree? . 165 8.4 What are packages? . 165 8.5 Should I use Ports or Packages? . 165 8.6 Is there any way to use my floppy drive if it's not attached during boot? . 165 8.7 OpenBSD Bootloader (i386, amd64 specific) . 166 8.8 S/Key . 166 8.9 What OpenBSD platforms support SMP? (Symmetric Multi-Processor)170 8.10 I get Input/output error when trying to use my tty devices . 171 8.11 What web browsers are available for OpenBSD? . 171 8.12 How do I use the mg editor? . 172 8.13 ksh(1) does not appear to read my .profile! . 173 8.14 Why does my /etc/motd file get overwritten when I modified it? 173 8.15 Antialiased and TrueType fonts in X . 173 8.16 Does OpenBSD support any journaling filesystems? . 173 8.17 Reverse DNS or Why is it taking so long for me to log in? . 174 8.18 Why do the OpenBSD web pages not conform to HTML4/XHTML?176 8.19 Why is my clock off by twenty-some seconds? . 176 8.20 Why is my clock off by several hours? . 176 CONTENTS 7 9 Migrating to OpenBSD 179 9.1 Tips for users of other Unix-like Operating Systems . 180 9.2 Dual booting Linux and OpenBSD . 182 9.3 Converting your Linux (or other Sixth Edition-style) password file to BSD-style . 183 9.4 Running Linux binaries on OpenBSD . 183 9.5 Accessing your Linux files from OpenBSD . 184 10 System Management 185 10.1 When I try to su to root it says that I'm in the.