.. _concepts-clustering-considerations:

Clustering 
------------

The cluster contains multiple nodes, which can be contained in separate, firewalled networks.  

Network ports need to be opened on firewalls to allow inter-node communication (described in more 
detail in the *Automate Platform Guide*).

All communication between nodes is encrypted.

+-----------+--------------------------------------------------------------------------------------------+
| Node type | Ports                                                                                      |
+===========+============================================================================================+
| Web proxy | 22 (ssh & sftp), 80 (http), 161 & 162 (snmp), 443 & 8443 (https)                           |
+-----------+--------------------------------------------------------------------------------------------+
| Unified   | 22 (ssh & sftp), 80 (http), 161 & 162 (snmp), 443 & 8443 (https), 27020 & 27030 (database) |
+-----------+--------------------------------------------------------------------------------------------+

.. note:: 

   * **22/ssh**:  Used for remote administration
   * **80 and 443**:  Used for the web server
   * **161 and 162**: Used for sending and receiving SNMP
   * **8443**: Used for inter-cluster communication
   * **27020 and 27030**:  Used for database queries and replication