WEB HOSTING Y DISEñO DE PÁGINAS WEB

Fuente: http://sunfreeware.com/openssh9.html

Openssh is meant to supply security to your systems. If you don't understand how to properly use it, you may have problems. Such problems are your responsibility. See our disclaimer. Please read the instructions below fully and carefully before you do any installation.

Installation of the openssh software on a Solaris machine is lengthy, but straightforward. To get ssh and sshd running you need to install a number of packages. There are a number of places on the net with details of this procedure. One of the best is on the Sun Blueprints web pages (in pdf format) at

Building and Deploying OpenSSH on Solaris[tm] Operating System (a pdf file)

or the

I do not use the Sun blueprint method exactly because some things have changed since that document was created.

Openssh requires that each machine have some sort of random (really pseudo- ) number generation. Solaris 9 and 10 come with /dev/random and /dev/urandom built in and so no outside software is needed. But, in the packages below I have supplied the prngd software that was used previously in case you wish to use that and make your own versions of openssl and openssh.
The seven pieces of software that may need to be on your system to use ssh properly are openssl, openssh, zlib, libgcc (you need this only if you do not have gcc 3.4.6 installed), and optionally egd, prngd, perl (there is a perl with Solaris 9 and 10 in /usr/bin), and tcp_wrappers. You can either download the sources and do the compiles yourself if you have a C compiler installed and working or you can go to sunfreeware.com and get pre-compiled packages. If you are very concerned about your machine's security and don't want to trust software compiled by someone else, then it is best for you to compile the software yourself. It is also a great learning experience.

The sources for these different programs are on sunfreeware.com or you can go to their home pages at

http://www.zlib.org zlib
http://www.perl.org perl
http://www.aet.tu-cottbus.de/personen/jaenicke/postfix_tls/prngd.html prngd
http://www.openssl.org openssl
http://www.openssh.org openssh
http://www.lothar.com/tech/crypto/ egd
ftp://ftp.porcupine.org/pub/security/index.html tcp_wrappers

I have included support for the optional use of the tcp_wrappers program (using the so-called Advanced Method). This can help to restrict the use of ssh logins to those computers defined in the so-called hosts.allow and hosts.deny files when set up properly. Ssh logins can also be logged using this software.

Installation Steps

To install the version of openssh from sunfreeware.com, go to the main page and select the files for SPARC/Solaris 9 or 10 at the right. For Intel/x86 download those files instead.

Or here are the files for example for Solaris 9 you need to download:

openssh-5.2p1-sol9-sparc-local.gz
openssl-0.9.8k-sol9-sparc-local.gz
tcp_wrappers-7.6-sol9-sparc-local.gz (optional, but recommended)
(unless you are using IPV6 - see the tcp_wrappers listing for details on this issue)
zlib-1.2.1-sol9-sparc-local.gz
perl-5.8.5-sol9-sparc-local.gz (optional)
prngd-0.9.25-sol9-sparc-local.gz (optional)
egd-0.8-sol9-sparc-local.gz (optional)

If you have already installed some of the above files, you can skip their downloads, but most are new.

Step Two: Installing the packages

With the files downloaded, go to the directory where you put them and run

# gunzip openssh-5.2p1-sol9-sparc-local.gz
# gunzip openssl-0.9.8k-sol9-sparc-local.gz
# gunzip zlib-1.2.1-sol9-sparc-local.gz
# gunzip libgcc-3.4.6-sol9-sparc-local.gz  (if you don't have gcc 3.4.6 installed)
# gunzip tcp_wrappers-7.6-sol9-sparc-local.gz (again optional)

and optionally for the other packages.  Then run as root

# pkgadd -d openssh-5.2p1-sol9-sparc-local
# pkgadd -d openssl-0.9.8k-sol9-sparc-local
# pkgadd -d zlib-1.2.1-sol9-sparc-local
# pkgadd -d libgcc-3.4.6-sol8-sparc-local  (if you don't have gcc 3.4.6 installed)
# pkgadd -d tcp_wrappers-7.6-sol9-sparc-local (optional)

Once you have installed the packages above, you will have files in various subdirectories of /usr/local. The default location for the ssl files is in /usr/local/ssl. While these files were compiled to avoid the need to put directories like /usr/local/lib and /usr/local/ssl/lib in your LD_LIBRARY_PATH, it is possible that you may need to set this. You should now find ssh in /usr/local/bin and sshd in /usr/local/sbin. Make sure you have /usr/local/bin and /usr/local/sbin in your PATH environment variable. Note also that if you are using Solaris 9 and 10, you may already have perl installed in your system. The perl scripts in the optional egd package (with .pl extensions) will look for perl in /usr/local/bin. If you are using the Sun perl, then the Perl programs will need to have /usr/bin at the beginning, while the sunfreeware Perl goes in /usr/local/bin.

Step Three: Setting up the sshd user and the /var/empty directory

In openssh 5.2p1, a new security method is setup called privilege separation. The details can be found in the README.privsep file in the openssh source distribution. This method is now the default in openssh. Before doing anything else, you should read the above document and if you agree, implement these steps as root:

# mkdir /var/empty
# chown root:sys /var/empty
# chmod 755 /var/empty
# groupadd sshd
# useradd -g sshd -c 'sshd privsep' -d /var/empty -s /bin/false sshd

/var/empty should not contain any files.

The default sshd_config file in /usr/local/etc has the last line

Subsystem sftp /usr/libexec/sftp-server

This may need to be changed to

Subsystem sftp /usr/local/libexec/sftp-server

If you do not do this and attempt to start up sshd, you will get error messages and the daemon will not start.

Step Four: Setting up tcp_wrappers

The next step it to setup tcp_wrappers. First read the README.tcpwrappers so that you know what tcp_wrappers does and how. Basically, tcp_wrappers is used to restrict to some limited group of machines access to your communication ports such as the port 22 that the sshd program uses. If you have tcp_wrappers running already, then you will only need to make sure that the sshd daemon entry is placed in the /etc/hosts.allow and /etc/hosts.deny files in a way that is appropriate to your setup. If you are not currently running tcp_wrappers, you can first create the file /etc/hosts.deny and put the single line

sshd: ALL

in it. Then, create the file /etc/hosts.allow file and put a line, for example, like

sshd: ... a list of the IP numbers of machine you want to be able to communicate with your machine separated by commas ...

in the file. We will test these entries later.

Step Five: Installing ssh and sshd

This is the final step. You should have read the README.openssl and INSTALL.openssl documents and you should also have read the openssh documents README.openssh and INSTALL.openssh.

Each machine that you want to communicate with via the ssh client will need to have an sshd daemon running. But first, you need to run the following three lines to create the key information for the server machine. Again, make sure you have /usr/local/bin and /usr/local/sbin in your PATH. If you have been running sshd before and have keys in /usr/local/etc, running these commands will overwrite them. As root, enter

# ssh-keygen -t rsa1 -f /usr/local/etc/ssh_host_key -N ""
# ssh-keygen -t dsa -f /usr/local/etc/ssh_host_dsa_key -N ""
# ssh-keygen -t rsa -f /usr/local/etc/ssh_host_rsa_key -N ""

and wait until each is done - this may take a few minutes depending on the speed of your machine.

You might also want to study the /usr/local/etc/ssh_config and /usr/local/etc/sshd_config files to see if there is anything you want to configure differently. The Sun version of ssh and sshd have configuration and key files in /etc/ssh which you may want to study also, though the packages here will not use them.

Now we can set up scripts to start the sshd daemon. In Solaris 9 and 10, there is an sshd script in /etc/init.d that start the Sun version of sshd during bootup. I use the following lines in the file /etc/init.d/sshd, but you may want to use modified versions of this or the Sun version. One possible script for Solaris 10 is There have been some comments on the net recently in the sun-managers mailing list that this script should be replaced. See the post below for details. I have received another idea for use with Solaris 10. See Solaris 10 startup at the end of this page.

#!/bin/sh

pid=`/usr/bin/ps -e | /usr/bin/grep sshd | /usr/bin/sed -e 's/^  *//' -e 's/ .*//'`
case $1 in
'start')
	/usr/local/sbin/sshd
	;;
'stop')
	if [ "${pid}" != "" ]
	then
		/usr/bin/kill ${pid}
	fi
	;;
*)
	echo "usage: /etc/init.d/sshd {start|stop}"
	;;
esac

Alternative Script Comment

Date: Mon, 13 Jan 2003 14:43:53 -0600 (CST)
From: "Mike's List" 
To: sunmanagers@sunmanagers.org
Subject: SUMMARY: sshd weirdness

Lots of responses on this one, I used the basic script below (from Luc).
Most responded that the script for the sunfreeware.com is badly written
and that the error or non-existence PID is from the grep to kill sshd.
I'm no script expert, only reporting what others replied.

Some recommends search for the /var/run/sshd.pid, this way your ssh
terminal won't get zap while sshd daemon is re-hup or stop/start.

Thanks all.


- Mike


case "$1" in
'start')
        if [ -x /usr/local/sbin/sshd ]; then
                echo "Starting the secure shell daemon"
                /usr/local/sbin/sshd &
        fi
        ;;

'stop')
        echo "Stopping the secure shell daemon "
        pkill -TERM sshd
        ;;
*)
        echo "Usage: /etc/init.d/sshd { start | stop }"
        ;;
esac
exit 0


On Fri, 10 Jan 2003, Mike's List wrote:

> Ok, quite a few asked to see the script (below) --Solaris 8 2/02 running
> sunfreeware.com openssh 3.7.1p2 --a couple of suggestions below doing
> 
> /bin/sh -x /etc/init.d/sshd stop
> 
> ...to see what's going on, I'm in the server remotely right now so I can't
> stop/start (because stop would just kills all the sshd processes and I
> can't get back in to start).
> 
> 
> - Mike
> 
> 
> #!/bin/sh
> pid=`/usr/bin/ps -e | /usr/bin/grep sshd | /usr/bin/sed -e 's/^  *//' -e 's/ .*//'`
> case $1 in
> 'start')
>         /usr/local/sbin/sshd
> ;;
> 'stop')
>         if [ "${pid}" != "" ]
>         then
>                 /usr/bin/kill ${pid}
>         fi
>         ;;
> *)
>         echo "usage: /etc/init.d/sshd {start|stop}"
>         ;;
> esac

End of Alternative Script Comment

# chown root /etc/init.d/sshd

# chgrp sys /etc/init.d/sshd

# chmod 555 /etc/init.d/sshd


# ln -s /etc/init.d/sshd /etc/rc2.d/S98sshd

# /etc/rc2.d/S98sshd start

will start the process if you want to do it by hand and

# /etc/rc2.d/S98sshd stop

will stop the sshd daemon. You can check this with

# ps -e | grep sshd

to see if sshd is running. If sshd is running and you have set up tcp_wrappers the way you want, then you can test the system. Of course, you have to have another machine that has the ssh program installed so that you can try to communicate with the machine on which you just started sshd. See the OpenSSH documentation for further details. To test that tcp_wrappers is working, you can put a machine's IP address in hosts.allow and see if you can ssh to the server machine from the client and then take it out and see if access is denied.

To repeat, if you have questions about the detailed use of any of these programs, please read the documentation first or go to their web sites. I do not want to know the security details of any of your systems and it would not be a good idea for you to tell me or anyone else. Security issues are very important and I strongly urge anyone to install as much security software as they can master and to keep a close eye out on the latest CERT and other vulnerability sites for announcements.

I am fully open to constructive suggestions on how make these instructions clearer or better and will include reasonable comments as they arrive.

Solaris 10 Alternative Startup Script

From: Ostrowski.Jamie

Just wanted to pass something along which I though might be helpful for 
those using the OpenSSH Packages tutorial for Solaris 10.

At the end of the writup, startup scripts are mentioned. I found that 
on Solaris 10, since it's using the newly modified svcs manifest startup 
software instead of the traditional startup scripts, I could modify it  to 
work with the new solaris 10 init config simply by:


1) Editing /lib/svc/method/sshd and changing the paths to sshd and 
ssh...specifically, these lines:


SSHDIR=/usr/local/etc/ssh
KEYGEN="/usr/local/bin/ssh-keygen -q"


and


'start')
         /usr/local/sbin/sshd

This will work with the new Solaris 10 init.

End of Solaris 10 Alternative Startup Script

© Copyright 2006 Steven M. Christensen and Associates, Inc.

This page was last updated on April 27, 2006.

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