SSH Tectia 
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    About This Document >>
    Installing SSH Tectia Server (M) >>
    Using SSH Tectia Server (M) >>
    Troubleshooting SSH Tectia Server (M) >>
    Configuration >>
    Authentication >>
        Server Authentication with Public Keys >>
        Server Authentication with Certificates >>
        User Authentication with Passwords
        User Authentication with Public Keys >>
        User Authentication with Certificates >>
        Host-Based User Authentication >>
        User Authentication with Keyboard-Interactive >>
            Client Configuration
            Server Configuration
            Pluggable Authentication Module (PAM) Submethod
            RSA SecurID Submethod
            RADIUS Submethod
        User Authentication with GSSAPI >>
    Application Tunneling >>
    Sample Files >>
    Man Pages
    Log Messages >>

Pluggable Authentication Module (PAM) Submethod

Pluggable Authentication Module is an authentication framework used in Unix systems. In SSH Tectia, support for PAM is enabled as a submethod of Keyboard-Interactive authentication.

When PAM is used, SSH Tectia Server (M) transfers the control of authentication to the PAM library, which will then load the modules specified in the PAM configuration file. Finally, the PAM library tells SSH Tectia Server (M) whether or not the authentication was successful. SSH Tectia Server (M) is not aware of the details of the actual authentication method employed by PAM. Only the final result is of interest.

To enable PAM support, include the following lines in the /etc/ssh2/sshd2_config file on the server:

AllowedAuthentications   keyboard-interactive
...
AuthKbdInt.Optional      pam

Include the following line in the /etc/ssh2/ssh2_config file on the client:

AllowedAuthentications   keyboard-interactive

The PAM configuration settings are located either in /etc/pam.conf or in /etc/pam.d/sshd2. The modules are usually either in the /lib/security directory or in the /usr/lib/security directory. Currently, SSH Tectia Server (M) supports PAM on Linux and on Solaris 2.6 or later.

There must be at least one auth, one account, and one session module in the configuration file. Otherwise the connection will be refused. Also, modules which require PAM_TTY will not work because TTY allocation is done in SSH Tectia Server (M) after the authentication.

See Section Keyboard-Interactive Authentication for more information on Keyboard-Interactive authentication.

Note: SSH Communications Security does not provide technical support on how to configure PAM. Our support only covers SSH Tectia applications.

PAM Examples

The following are examples of different PAM configurations.

PAM on Red Hat Linux

The /etc/pam.d/sshd2 file on Red Hat Linux:

auth     required /lib/security/pam_pwdb.so shadow nullok
auth     required /lib/security/pam_nologin.so
account  required /lib/security/pam_pwdb.so
password required /lib/security/pam_cracklib.so
password required /lib/security/pam_pwdb.so shadow nullok use_authtok
session  required /lib/security/pam_pwdb.so

On SUSE LINUX, the configuration is otherwise the same but pam_unix.so is used instead of pam_pwdb.so.

PAM on Sun Solaris

The /etc/pam.conf entry on Solaris:

sshd2  auth      required  /usr/lib/security/pam_unix.so debug 
sshd2  account   required  /usr/lib/security/pam_unix.so debug 
sshd2  password  required  /usr/lib/security/pam_unix.so debug
sshd2  session   required  /usr/lib/security/pam_unix.so debug

PAM Used with LDAP on Red Hat Linux

The following is an example on how to configure PAM to use LDAP authentication on a Red Hat 9 machine. Before trying this setup, verify that PAM works for local accounts.

In the file /etc/pam.d/sshd2, add the following:

auth     required /lib/security/pam_ldap.so
account  required /lib/security/pam_ldap.so
password required /lib/security/pam_ldap.so
session  required /lib/security/pam_ldap.so

In the file /etc/nsswitch.conf, add the following:

passwd: files ldap
shadow: files ldap
group: files ldap

In the file /etc/ldap.conf, add the following:

host ldapserver.company.com
base dc=company,dc=com
ldap_version 3
port 389
scope one
pam_min_uid 10000
pam_max_uid 20000
nss_base_passwd ou=accounts,dc=company,dc=com?one
nss_base_shadow ou=accounts,dc=company,dc=com?one
nss_base_group ou=groups,dc=company,dc=com?one
ssl no
pam_password md5

This is just an example and needs to be modified according to your LDAP server configuration.

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