Using SSL Communication with Linux-Based Agents

You can secure communication between the up.time monitoring station and the up.time Linux agent by enabling SSL encryption. Enabling SSL is a two-step process:

• Enabling SSL on the Linux Agent System
• Enabling SSL in the up.time GUI

Enabling SSL on the Linux Agent System

To enable SSL encryption, complete the following steps on each agent system:

NOTE: Do not perform these steps on the monitoring station.

1. Ensure Stunnel is installed on the agent server. If you do not have access to a distribution, you can download it from Stunnel.org.
2. Edit the /etc/xinetd.d/uptimeagent file so that it includes the following configuration information:

   service uptimeagent
   {
           disable         = no
           flags           = REUSE
           socket_type     = stream
           wait            = no
           user            = nobody
           server          = /usr/sbin/stunnel
           server_args     = /etc/stunnel/uptimeagent.conf
   }
   

3. Create the certificate that will be used by Stunnel. For example:
   

   openssl req -new -x509 -days 365 -nodes -config stunnel.cnf -out stunnel.pem -keyout stunnel.pem
   

   The following is a sample stunnel.cnf for the openssl program:

   
   # create RSA certs - Server
   
   RANDFILE = stunnel.rnd
   
   [ req ]
   default_bits = 1024
   encrypt_key = yes
   distinguished_name = req_dn
   x509_extensions = cert_type
   
   [ req_dn ]
   countryName = Country Name (2 letter code)
   countryName_default             = PL
   countryName_min                 = 2
   countryName_max                 = 2
   
   stateOrProvinceName             = State or Province Name (full name)
   stateOrProvinceName_default     = Some-State
   
   localityName                    = Locality Name (eg, city)
   
   0.organizationName              = Organization Name (eg, company)
   0.organizationName_default      = Stunnel Developers Ltd
   
   organizationalUnitName          = Organizational Unit Name (eg, section)
   #organizationalUnitName_default =
   
   0.commonName                    = Common Name (FQDN of your server)
   0.commonName_default            = localhost
   
   # To create a certificate for more than one name uncomment:
   # 1.commonName                  = DNS alias of your server
   # 2.commonName                  = DNS alias of your server
   # ...
   # See http://home.netscape.com/eng/security/ssl_2.0_certificate.html
   # to see how Netscape understands commonName.
   
   [ cert_type ]
   nsCertType = server
   

4. Copy stunnel.pem to /etc/stunnel/uptimeagent.pem.



NOTE: Permissions on the uptimeagent.pem should be set to 600 with the uptimeagent as the owner otherwise a permissions issue may be encountered when the agent is called.

5. Create the /etc/stunnel/uptimeagent.conf file and add the following lines:

   cert=/etc/stunnel/uptimeagent.pem
   exec=/opt/uptime-agent/bin/uptimeagent
   

6. Restart the xinetd service. After doing this, your agent should now be in SSL mode.

   You can verify that your agent is communicating securely by running the following command on your monitoring station:

   agentcmd +s -p 9998 <hostname> df-k
    

   NOTE: You can change the port on which to enable SSL to any value. To change the default agent port to something other than 9998, edit the /etc/services file, and restart xinetd. You can also use the agent-configure.sh script (see Setting the agent port or permissions for more information).

Enabling SSL in the up.time UI

If the Linux agent has already been added to up.time, complete the following steps in the up.time Web interface for each agent system that you want to configure to use SSL.

1. Click My Enterprise.
2. Click the name of the agent system for which you want to enable SSL.
3. On the system information page, click the Edit Performance Monitor link in the System Profile section.
4. In the new Edit Service Monitor window that appears, select the Use SSL (HTTPS) option.
5. Click Save.
   
   Once saved, your monitoring station and agent system will be communicating via SSL.

If you have not yet added the agent system to up.time, follow the steps that are detailed in the up.time User Guide. When adding the agent system, ensure that the Agent Port Number option is set to 9998, and that the Use SSL (HTTPS) option is enabled.