==========================
Connection on PSMN servers
==========================

.. IMPORTANT:: For your **First connection** please follow :doc:`these instructions <first_connection>` to generate your PSMN :term:`SSH` key pair

To work on PSMN cluster, you need firstly to connect to ``allo-psmn``, which allows to connect to one of PSMN :doc:`front-end servers (login nodes) <../clusters_usage/login_nodes>`. The connection to ``allo-psmn`` is working directly from  ENS network, or via a gateway server from outside of ENS network :

.. figure:: /_static/synoptique_ssh_hops.png
    :alt: PSMN internal/external connections synoptic
    :align: center

    Internal or External PSMN gateways synoptic

.. WARNING:: ``allo-psmn`` is a connection server, it only allows you to access and to transfer your files and **that's all**.

    Its only purpose is to connect to the PSMN's network to access front machines. To work on PSMN cluster, you need to connect from ``allo-psmn`` to one of the :doc:`front-end servers (login nodes) <../clusters_usage/login_nodes>`.


From ENS network
================

To connect to PSMN cluster, you need to use :term:`SSH`. The easiest way is to use the following command:

  * From a Linux or a  MacOS X computer, open a terminal and type:

.. code-block:: bash

    ssh mylogin@allo-psmn.psmn.ens-lyon.fr
    # enter your PSMN password, as asked

replace ``mylogin`` by your login (as provided by PSMN).

  * From a  Windows computer, refer to :doc:`OpenSSH activation for Windows 10 <openssh_on_windows10>`. 


From outside ENS network
========================

In order to connect on ``allo-psmn`` from outside ENS network, you must use one of the :term:`SSH` gateways:

  * ``ssh.psmn.ens-lyon.fr``
  * or ``ssh.ens-lyon.fr``, if you have an user account at ENS de Lyon,

  .. WARNING:: ``ssh.psmn`` and ``ssh.ens`` are connection servers (or gateways). There is **no home space** on it (~5MiB max). Your real home starts at ``allo-psmn``.

.. figure:: /_static/synoptique_gateways+hops.png
    :alt: PSMN gateways synoptic
    :align: center

    PSMN gateways synoptic (``ssh.ens`` or ``ssh.psmn``)


Therefore, in order to connect on ``allo-psmn`` from outside ENS network, first you need to connect to the :term:`SSH` gateway ``ssh.psmn.ens-lyon.fr`` (or ``ssh.ens-lyon.fr``), then you can connect to ``allo-psmn``:

.. code-block:: bash

    ssh mylogin@ssh.psmn.ens-lyon.fr (or ssh mylogin@ssh.ens-lyon.fr)
    # enter your PSMN password (or ENS password), as asked
    # then
    ssh mylogin@allo-psmn.psmn.ens-lyon.fr
    # enter your PSMN password, as asked





One-step connection:
--------------------

.. code-block:: bash

    ssh -X -oProxyCommand="ssh mylogin@ssh.psmn.ens-lyon.fr netcat -w1 allo-psmn %p" mylogin@allo-psmn.psmn.ens-lyon.fr
    # you'll have to give your PSMN password twice

or

.. code-block:: bash

    ssh -X -oProxyCommand="ssh mylogin@ssh.ens-lyon.fr netcat -w1 allo-psmn %p" mylogin@allo-psmn.psmn.ens-lyon.fr
    # you'll have to give your ENS password, then your PSMN password 


.. IMPORTANT:: For your **First connection** please follow :doc:`these instructions <first_connection>` to generate your PSMN :term:`SSH` key pair


.. WARNING:: ``allo-psmn`` is a connection server, it only allows you to access and to transfer your files and **that's all**.

    Its only purpose is to connect to the PSMN's network to access front machines. To work on PSMN cluster, you need to connect from ``allo-psmn`` to one of the :doc:`front-end servers (login nodes) <../clusters_usage/login_nodes>`.