4 A C compiler. Any C89 or better compiler should work. Where supported,
5 configure will attempt to enable the compiler's run-time integrity checking
6 options. Some notes about specific compilers:
7 - clang: -ftrapv and -sanitize=integer require the compiler-rt runtime
8 (CC=clang LDFLAGS=--rtlib=compiler-rt ./configure)
10 You will need working installations of Zlib and libcrypto (LibreSSL /
13 Zlib 1.1.4 or 1.2.1.2 or greater (earlier 1.2.x versions have problems):
14 http://www.gzip.org/zlib/
16 libcrypto (LibreSSL or OpenSSL >= 0.9.8f < 1.1.0)
17 LibreSSL http://www.libressl.org/ ; or
18 OpenSSL http://www.openssl.org/
20 LibreSSL/OpenSSL should be compiled as a position-independent library
21 (i.e. with -fPIC) otherwise OpenSSH will not be able to link with it.
22 If you must use a non-position-independent libcrypto, then you may need
23 to configure OpenSSH --without-pie. Note that because of API changes,
24 OpenSSL 1.1.x is not currently supported.
26 The remaining items are optional.
28 NB. If you operating system supports /dev/random, you should configure
29 libcrypto (LibreSSL/OpenSSL) to use it. OpenSSH relies on libcrypto's
30 direct support of /dev/random, or failing that, either prngd or egd
34 If your system lacks kernel-based random collection, the use of Lutz
35 Jaenicke's PRNGd is recommended.
37 http://prngd.sourceforge.net/
41 If the kernel lacks /dev/random the Entropy Gathering Daemon (EGD) is
42 supported only if libcrypto supports it.
44 http://egd.sourceforge.net/
48 OpenSSH can utilise Pluggable Authentication Modules (PAM) if your
49 system supports it. PAM is standard most Linux distributions, Solaris,
50 HP-UX 11, AIX >= 5.2, FreeBSD and NetBSD.
52 Information about the various PAM implementations are available:
54 Solaris PAM: http://www.sun.com/software/solaris/pam/
55 Linux PAM: http://www.kernel.org/pub/linux/libs/pam/
56 OpenPAM: http://www.openpam.org/
58 If you wish to build the GNOME passphrase requester, you will need the GNOME
59 libraries and headers.
64 Alternatively, Jim Knoble <jmknoble@pobox.com> has written an excellent X11
65 passphrase requester. This is maintained separately at:
67 http://www.jmknoble.net/software/x11-ssh-askpass/
71 If you wish to use the TCP wrappers functionality you will need at least
72 tcpd.h and libwrap.a, either in the standard include and library paths,
73 or in the directory specified by --with-tcp-wrappers. Version 7.6 is
76 http://ftp.porcupine.org/pub/security/index.html
80 If you wish to use --with-skey then you will need the library below
81 installed. No other S/Key library is currently known to be supported.
83 http://www.sparc.spb.su/solaris/skey/
87 sftp supports command-line editing via NetBSD's libedit. If your platform
88 has it available natively you can use that, alternatively you might try
89 these multi-platform ports:
91 http://www.thrysoee.dk/editline/
92 http://sourceforge.net/projects/libedit/
96 LDNS is a DNS BSD-licensed resolver library which supports DNSSEC.
98 http://nlnetlabs.nl/projects/ldns/
102 If you modify configure.ac or configure doesn't exist (eg if you checked
103 the code out of CVS yourself) then you will need autoconf-2.69 to rebuild
104 the automatically generated files by running "autoreconf". Earlier
105 versions may also work but this is not guaranteed.
107 http://www.gnu.org/software/autoconf/
109 Basic Security Module (BSM):
111 Native BSM support is known to exist in Solaris from at least 2.5.1,
112 FreeBSD 6.1 and OS X. Alternatively, you may use the OpenBSM
113 implementation (http://www.openbsm.org).
116 2. Building / Installation
117 --------------------------
119 To install OpenSSH with default options:
125 This will install the OpenSSH binaries in /usr/local/bin, configuration files
126 in /usr/local/etc, the server in /usr/local/sbin, etc. To specify a different
127 installation prefix, use the --prefix option to configure:
129 ./configure --prefix=/opt
133 Will install OpenSSH in /opt/{bin,etc,lib,sbin}. You can also override
134 specific paths, for example:
136 ./configure --prefix=/opt --sysconfdir=/etc/ssh
140 This will install the binaries in /opt/{bin,lib,sbin}, but will place the
141 configuration files in /etc/ssh.
143 If you are using Privilege Separation (which is enabled by default)
144 then you will also need to create the user, group and directory used by
145 sshd for privilege separation. See README.privsep for details.
147 If you are using PAM, you may need to manually install a PAM control
148 file as "/etc/pam.d/sshd" (or wherever your system prefers to keep
149 them). Note that the service name used to start PAM is __progname,
150 which is the basename of the path of your sshd (e.g., the service name
151 for /usr/sbin/osshd will be osshd). If you have renamed your sshd
152 executable, your PAM configuration may need to be modified.
154 A generic PAM configuration is included as "contrib/sshd.pam.generic",
155 you may need to edit it before using it on your system. If you are
156 using a recent version of Red Hat Linux, the config file in
157 contrib/redhat/sshd.pam should be more useful. Failure to install a
158 valid PAM file may result in an inability to use password
159 authentication. On HP-UX 11 and Solaris, the standard /etc/pam.conf
160 configuration will work with sshd (sshd will match the other service
163 There are a few other options to the configure script:
165 --with-audit=[module] enable additional auditing via the specified module.
166 Currently, drivers for "debug" (additional info via syslog) and "bsm"
167 (Sun's Basic Security Module) are supported.
169 --with-pam enables PAM support. If PAM support is compiled in, it must
170 also be enabled in sshd_config (refer to the UsePAM directive).
172 --with-prngd-socket=/some/file allows you to enable EGD or PRNGD
173 support and to specify a PRNGd socket. Use this if your Unix lacks
174 /dev/random and you don't want to use OpenSSH's builtin entropy
177 --with-prngd-port=portnum allows you to enable EGD or PRNGD support
178 and to specify a EGD localhost TCP port. Use this if your Unix lacks
179 /dev/random and you don't want to use OpenSSH's builtin entropy
182 --with-lastlog=FILE will specify the location of the lastlog file.
183 ./configure searches a few locations for lastlog, but may not find
184 it if lastlog is installed in a different place.
186 --without-lastlog will disable lastlog support entirely.
188 --with-osfsia, --without-osfsia will enable or disable OSF1's Security
189 Integration Architecture. The default for OSF1 machines is enable.
191 --with-skey=PATH will enable S/Key one time password support. You will
192 need the S/Key libraries and header files installed for this to work.
194 --with-tcp-wrappers will enable TCP Wrappers (/etc/hosts.allow|deny)
197 --with-md5-passwords will enable the use of MD5 passwords. Enable this
198 if your operating system uses MD5 passwords and the system crypt() does
199 not support them directly (see the crypt(3/3c) man page). If enabled, the
200 resulting binary will support both MD5 and traditional crypt passwords.
202 --with-utmpx enables utmpx support. utmpx support is automatic for
205 --without-shadow disables shadow password support.
207 --with-ipaddr-display forces the use of a numeric IP address in the
208 $DISPLAY environment variable. Some broken systems need this.
210 --with-default-path=PATH allows you to specify a default $PATH for sessions
211 started by sshd. This replaces the standard path entirely.
213 --with-pid-dir=PATH specifies the directory in which the sshd.pid file is
216 --with-xauth=PATH specifies the location of the xauth binary
218 --with-ssl-dir=DIR allows you to specify where your Libre/OpenSSL
222 --with-ssl-engine enables Libre/OpenSSL's (hardware) ENGINE support
224 --with-4in6 Check for IPv4 in IPv6 mapped addresses and convert them to
225 real (AF_INET) IPv4 addresses. Works around some quirks on Linux.
227 If you need to pass special options to the compiler or linker, you
228 can specify these as environment variables before running ./configure.
231 CFLAGS="-O -m486" LDFLAGS="-s" LIBS="-lrubbish" LD="/usr/foo/ld" ./configure
236 The runtime configuration files are installed by in ${prefix}/etc or
237 whatever you specified as your --sysconfdir (/usr/local/etc by default).
239 The default configuration should be instantly usable, though you should
240 review it to ensure that it matches your security requirements.
242 To generate a host key, run "make host-key". Alternately you can do so
243 manually using the following commands:
245 ssh-keygen -t [type] -f /etc/ssh/ssh_host_key -N ""
247 for each of the types you wish to generate (rsa, dsa or ecdsa) or
251 to generate keys for all supported types.
253 Replacing /etc/ssh with the correct path to the configuration directory.
254 (${prefix}/etc or whatever you specified with --sysconfdir during
257 If you have configured OpenSSH with EGD support, ensure that EGD is
258 running and has collected some Entropy.
260 For more information on configuration, please refer to the manual pages
261 for sshd, ssh and ssh-agent.
263 4. (Optional) Send survey
264 -------------------------
267 [check the contents of the file "survey" to ensure there's no information
268 that you consider sensitive]
271 This will send configuration information for the currently configured
272 host to a survey address. This will help determine which configurations
273 are actually in use, and what valid combinations of configure options
274 exist. The raw data is available only to the OpenSSH developers, however
275 summary data may be published.
280 If you experience problems compiling, installing or running OpenSSH.
281 Please refer to the "reporting bugs" section of the webpage at
282 https://www.openssh.com/