1. Prerequisites
----------------

You will need working installations of Zlib and OpenSSL.

Zlib:
http://www.freesoftware.com/pub/infozip/zlib/

OpenSSL 0.9.5a or greater:
http://www.openssl.org/

RPMs of OpenSSL are available at http://violet.ibs.com.au/openssh/files/support

OpenSSH can utilise Pluggable Authentication Modules (PAM) if your system
supports it. PAM is standard on Redhat and Debian Linux, Solaris and
HP-UX 11.

PAM:
http://www.kernel.org/pub/linux/libs/pam/

If you wish to build the GNOME passphrase requester, you will need the GNOME
libraries and headers.

GNOME:
http://www.gnome.org/

Alternatively, Jim Knoble <jmknoble@pobox.com> has written an excellent X11
passphrase requester. This is maintained separately at:

http://www.ntrnet.net/~jmknoble/software/x11-ssh-askpass/index.html

The Entropy Gathering Daemon (EGD) is supported if you have a system which
lacks /dev/random and don't want to use OpenSSH's internal entropy collection.

EGD:
http://www.lothar.com/tech/crypto/

GNU Make:
ftp://ftp.gnu.org/gnu/make/

OpenSSH has only been tested with GNU make. It may work with other
'make' programs, but you are on your own.

pcre (POSIX Regular Expression library):
ftp://ftp.cus.cam.ac.uk/pub/software/programs/pcre/

Most platforms do not required this.  However older 4.3 BSD do not
have a posix regex library. 

S/Key Libraries:
http://www.sparc.spb.su/solaris/skey/

If you wish to use --with-skey then you will need the above library
installed.  No other current S/Key library is currently known to be
supported. 

2. Building / Installation
--------------------------

To install OpenSSH with default options:

./configure
make
make install

This will install the OpenSSH binaries in /usr/local/bin, configuration files
in /usr/local/etc, the server in /usr/local/sbin, etc. To specify a different
installation prefix, use the --prefix option to configure:

./configure --prefix=/opt
make
make install

Will install OpenSSH in /opt/{bin,etc,lib,sbin}. You can also override 
specific paths, for example:

./configure --prefix=/opt --sysconfdir=/etc/ssh
make
make install

This will install the binaries in /opt/{bin,lib,sbin}, but will place the
configuration files in /etc/ssh.

If you are using PAM, you may need to manually install a PAM
control file as "/etc/pam.d/sshd" (or wherever your system
prefers to keep them). A generic PAM configuration is included as
"contrib/sshd.pam.generic", you may need to edit it before using it on
your system. If you are using a recent version of Redhat Linux, the
config file in contrib/redhat/sshd.pam should be more useful. 
Failure to install a valid PAM file may result in an inability to
use password authentication.  On HP-UX 11, the standard /etc/pam.conf
configuration will work with sshd (sshd will match the OTHER service
name).

There are a few other options to the configure script:

--with-rsh=PATH allows you to specify the path to your rsh program. 
Normally ./configure will search the current $PATH for 'rsh'. You 
may need to specify this option if rsh is not in your path or has a
different name.

--without-pam will disable PAM support. PAM is automatically detected 
and switched on if found.

--enable-gnome-askpass will build the GNOME passphrase dialog. You
need a working installation of GNOME, including the development
headers, for this to work.

--with-random=/some/file allows you to specify an alternate source of
random numbers (the default is /dev/urandom). Unless you are absolutely
sure of what you are doing, it is best to leave this alone.

--with-egd-pool=/some/file allows you to enable Entropy Gathering
Daemon support and to specify a EGD pool socket. Use this if your
Unix lacks /dev/random and you don't want to use OpenSSH's builtin
entropy collection support.

--with-lastlog=FILE will specify the location of the lastlog file. 
./configure searches a few locations for lastlog, but may not find
it if lastlog is installed in a different place.

--without-lastlog will disable lastlog support entirely.

--with-kerberos4=PATH will enable Kerberos IV support. You will need
to have the Kerberos libraries and header files installed for this
to work. Use the optional PATH argument to specify the root of your
Kerberos installation.

--with-afs=PATH will enable AFS support. You will need to have the
Kerberos IV and the AFS libraries and header files installed for this
to work.  Use the optional PATH argument to specify the root of your
AFS installation. AFS requires Kerberos support to be enabled.

--with-skey=PATH will enable S/Key one time password support. You will 
need the S/Key libraries and header files installed for this to work.

--with-tcp-wrappers will enable TCP Wrappers (/etc/hosts.allow|deny)
support. You will need libwrap.a and tcpd.h installed.

--with-md5-passwords will enable the use of MD5 passwords. Enable this
if your operating system uses MD5 passwords without using PAM.

--with-utmpx enables utmpx support. utmpx support is automatic for 
some platforms.

--without-shadow disables shadow password support.

--with-ipaddr-display forces the use of a numeric IP address in the 
$DISPLAY environment variable. Some broken systems need this.

--with-default-path=PATH allows you to specify a default $PATH for sessions
started by sshd. This replaces the standard path entirely.

--with-pid-dir=PATH specifies the directory in which the ssh.pid file is
created.

--with-xauth=PATH specifies the location of the xauth binary

--with-ipv4-default instructs OpenSSH to use IPv4 by default for new
connections. Normally OpenSSH will try attempt to lookup both IPv6 and
IPv4 addresses. On Linux/glibc-2.1.2 this causes long delays in name
resolution. If this option is specified, you can still attempt to 
connect to IPv6 addresses using the command line option '-6'.

--with-ssl-dir=DIR allows you to specify where your OpenSSL libraries
are installed.

--with-4in6 Check for IPv4 in IPv6 mapped addresses and convert them to
real (AF_INET) IPv4 addresses. Works around some quirks on Linux.

If you need to pass special options to the compiler or linker, you
can specify these as environment variables before running ./configure.
For example:

CFLAGS="-O -m486" LDFLAGS="-s" LIBS="-lrubbish" LD="/usr/foo/ld" ./configure

3. Configuration
----------------

The runtime configuration files are installed by in ${prefix}/etc or 
whatever you specified as your --sysconfdir (/usr/local/etc by default).

The default configuration should be instantly usable, though you should 
review it to ensure that it matches your security requirements.

To generate a host key, run "make host-key". Alternately you can do so
manually using the following commands: 

    ssh-keygen -b 1024 -f /etc/ssh/ssh_host_key -N ""
    ssh-keygen -d -f /etc/ssh/ssh_host_dsa_key -N ""

Replacing /etc/ssh with the correct path to the configuration directory.
(${prefix}/etc or whatever you specified with --sysconfdir during 
configuration)

If you have configured OpenSSH with EGD support, ensure that EGD is
running and has collected some Entropy.

For more information on configuration, please refer to the manual pages 
for sshd, ssh and ssh-agent.

4. Problems?
------------

If you experience problems compiling, installing or running OpenSSH. 
Please refer to the "reporting bugs" section of the webpage at
http://www.openssh.com/