====== RSH por SSH ======

===== Descripción =====

 Como usar ssh sin password

===== Prerequistos =====

 Esto permite ejecutar un comando remoto si necesidad de ingresar una contraseña .. pero pues bien inseguro asi que cierre la vaina bien.

===== Procedimiento =====

===== A. Solo intercambio de llaves de usuarios =====

La otra opcion es con intercambio de llaves y no mas

  - Ejecute   ssh-keygen -t rsa
  - Copia en el archivo /suario/.ssh/id_dsa.pub(en el cliente) en /otrousuario/.ssh/authorized_keys2 (en el servidor)
  - Ponga permisos 600 al authorized_keys2   y el .ssh debe ser 700 usualmente

y voila \\
 

===== B. Identificacion de maquinas =====

==== 1. Instalación Basica (Consola) ====

Por seguridad vayanse siempre con protocolo version2.

Debe crear un archivo /etc/shost.equiv con los nombres de los servidores confiables y en el directorio del usuario crear un .shosts con el nombre del servidor remoto  y de su usuario equivalente. (mirar anexo)

==== 2. Configuracion de SSH ====

Agregue las opciones

<code>
HostbasedAuthentication yesProtocol 2EnableSSHKeysign yes 
</code>

==== 3. Ahora pa que levante SSHD ====

Agregue las opciones

<code>
HostbasedAuthentication yes
</code>

==== 4. Posibles Problemas ====

Cuando ssh-keysign no es suid .. se ve

I>>>>>>>>>>> debug1: Next authentication method: hostbased\\
I>>>>>>>>>>> could not open any host key\\
I>>>>>>>>>>> ssh_keysign: no reply

===== Problemas =====

==== 1.- No funciona ====

Un problema es que el authorized_keys y authorized_keys2 deben existir\\
ambos

Debe ponerse passphrase ..pero sin ella es mas facil

===== Referencias =====

-

http:%%//%%www.cs.umd.edu/~arun/misc/ssh.html o su copia local [[egw/egw_docroot/wiki/docs/ssh_without_pass.html|ssh_without_pass.html]]

http:%%//%%www.csua.berkeley.edu/~ranga/notes/ssh_nopass.html o su copia local [[egw/egw_docroot/wiki/docs/ssh_nopass.html|ssh_nopass.html]]

 

FIN

==============================================================
=========================================================================
Anexo /etc/ssh/ssh_config
=========================================================================


# $OpenBSD: ssh_config,v 1.19 2003/08/13 08:46:31 markus Exp $

# This is the ssh client system-wide configuration file.  See
# ssh_config(5) for more information.  This file provides defaults for
# users, and the values can be changed in per-user configuration files
# or on the command line.

# Configuration data is parsed as follows:
#  1. command line options
#  2. user-specific file
#  3. system-wide file
# Any configuration value is only changed the first time it is set.
# Thus, host-specific definitions should be at the beginning of the
# configuration file, and defaults at the end.

# Site-wide defaults for various options

# Host *
#   ForwardAgent no
#   ForwardX11 no
#   ForwardX11Trusted yes
#   RhostsRSAAuthentication yes
#   RSAAuthentication yes
#   PasswordAuthentication yes
HostbasedAuthentication yes
#   BatchMode no
#   CheckHostIP yes
#   AddressFamily any
#   ConnectTimeout 0
#   StrictHostKeyChecking ask
#   IdentityFile ~/.ssh/identity
#   IdentityFile ~/.ssh/id_rsa
#   IdentityFile ~/.ssh/id_dsa
#   Port 22
#   Protocol 2,1
Protocol 2
#   Cipher 3des
#   Ciphers aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,aes192-cbc,aes256-cbc
#   EscapeChar ~

#############

EnableSSHKeysign yes


=========================================================================
Anexo /etc/ssh/sshd_config
=========================================================================

# Package generated configuration file
# See the sshd(8) manpage for defails

# What ports, IPs and protocols we listen for
Port 22
# Use these options to restrict which interfaces/protocols sshd will bind to
#ListenAddress ::
#ListenAddress 0.0.0.0
Protocol 2
# HostKeys for protocol version 2
HostKey /etc/ssh/ssh_host_rsa_key
HostKey /etc/ssh/ssh_host_dsa_key
#Privilege Separation is turned on for security
UsePrivilegeSeparation yes

# ...but breaks Pam auth via kbdint, so we have to turn it off
# Use PAM authentication via keyboard-interactive so PAM modules can
# properly interface with the user (off due to PrivSep)
#PAMAuthenticationViaKbdInt no
# Lifetime and size of ephemeral version 1 server key
KeyRegenerationInterval 3600
ServerKeyBits 768

# Logging
SyslogFacility AUTH
LogLevel INFO

# Authentication:
LoginGraceTime 600
PermitRootLogin no
StrictModes yes

RSAAuthentication yes
PubkeyAuthentication yes
#AuthorizedKeysFile %h/.ssh/authorized_keys

# rhosts authentication should not be used
#RhostsAuthentication no
# Don't read the user's ~/.rhosts and ~/.shosts files
IgnoreRhosts no
# For this to work you will also need host keys in /etc/ssh_known_hosts
RhostsRSAAuthentication no
# similar for protocol version 2
HostbasedAuthentication yes
# Uncomment if you don't trust ~/.ssh/known_hosts for RhostsRSAAuthentication
#IgnoreUserKnownHosts yes

# To enable empty passwords, change to yes (NOT RECOMMENDED)
PermitEmptyPasswords no

# Uncomment to disable s/key passwords
#ChallengeResponseAuthentication no

# To disable tunneled clear text passwords, change to no here!
PasswordAuthentication yes


# To change Kerberos options
#KerberosAuthentication no
#KerberosOrLocalPasswd yes
#AFSTokenPassing no
#KerberosTicketCleanup no

# Kerberos TGT Passing does only work with the AFS kaserver
#KerberosTgtPassing yes

X11Forwarding no
X11DisplayOffset 10
PrintMotd no
#PrintLastLog no
KeepAlive yes
#UseLogin no

#MaxStartups 10:30:60
#Banner /etc/issue.net
#ReverseMappingCheck yes

Subsystem sftp /usr/lib/sftp-server


UsePAM yes

=========================================================================
Anexo /etc/shosts.equiv
=========================================================================

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=========================================================================
Anexo $HOME/.shosts
=========================================================================

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=========================================================================

15-Marzo-2006 J.E.Gomez v1.0 Primera version\\
14-Mayo-2005 J.E.Gomez v0.5

 



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