Secure Jetty with HTTPS

If you access the Horizon web UI via untrusted networks, it is best practice to use HTTPS to protect incoming web sessions. This section explains how to configure Horizon’s built-in Jetty web server to support HTTPS.

It is typically easier to leave the Jetty config as default and use NGINX or Apache as a reverse proxy. See How to use NGINX as an SSL proxy with OpenNMS Horizon on Discourse for an example of using a reverse proxy.

Customize jetty.xml

By default, no Jetty configuration file is included in Horizon. There is, however, a sample jetty.xml file in ${OPENNMS_HOME}/etc/examples that you can use as a template. Copy the file to ${OPENNMS_HOME}/etc, open it in a text editor, and remove the comment tags from the "Add HTTPS Support" section.

Create a new Java keystore

Open the keytool utility that ships in ${JAVA_HOME}/bin/keytool with most Java distributions, and create a new keystore. Populate it with a new key and, for the first question ("What is your first and last name?"), enter the fully-qualified domain name by which users will access the Horizon web UI.

Type this name correctly; you will have to start this process over if it ever needs to be changed.

Answer the remaining questions according to the specifics of your organization and location.

Make sure that you specify an appropriate number of days for the validity parameter. After the defined number of days elapses, the key will expire and you may no longer be able to use it to create new certificates. The example below specifies 731 days, which makes the key valid for two years (accounting for a possible leap year).

It is important that you choose secure passwords for the keystore, and for the key itself. These passwords may be the same as or different from each other. Using different passwords protects your server’s private key in the event that the keystore file falls into the wrong hands. You should take precautions to keep this from happening, including setting filesystem user and group permissions so that unauthorized individuals with accounts on the Horizon server will not have read or write access to the keystore.

By default, the keytool creates DSA keys, but Jetty requires an RSA key. Make sure that you pass the -keyalg RSA option to the keytool to generate an RSA key:

keytool -alias opennms-jetty -genkeypair -keyalg RSA -keysize 2048 -validity 731 -keystore /tmp/propercert/proper.keystore
Enter keystore password:  aGoodStrongKeystorePassword
What is your first and last name?
What is the name of your organizational unit?
  [Unknown]:  Network Management Division
What is the name of your organization?
  [Unknown]:  The Example Organization
What is the name of your City or Locality?
  [Unknown]:  Marina del Rey
What is the name of your State or Province?
  [Unknown]:  California
What is the two-letter country code for this unit?
  [Unknown]:  US
Is, OU=Network Management Division, O=The Example Organization, L=Marina del Rey, ST=California, C=US correct?
  [no]:  yes

Create or edit ${OPENNMS_HOME}/etc/ to set the Jetty certificate information. Adjust the values based on the values set when using the keytool command to create the keystore and certificate.

org.opennms.netmgt.jetty.https-port = 8443
org.opennms.netmgt.jetty.https-keystore = /opt/opennms/etc/opennms.keystore
org.opennms.netmgt.jetty.https-keystorepassword = keystore-password
org.opennms.netmgt.jetty.https-keypassword = key-password
org.opennms.netmgt.jetty.https-cert-alias = opennms-jetty

Restrict access to the plain-HTTP listener

The process of configuring Horizon to start a Jetty HTTPS listener on port 8443 does not include disabling the plain-HTTP listener that is present by default on port 8980. This listener must be present so the Horizon real-time console can update availability statistics shown in the web UI.

After you have enabled HTTPS, you likely do not want users using HTTP; to control this, you must restrict access to the plain-HTTP listener. There are two methods to accomplish this:

  • Set the plain-HTTP listener to bind only to an interface that is not accessible from untrusted networks. In an environment where the Horizon web UI runs on the same server as the other OpenNMS daemons, it makes sense to use the loopback interface for this purpose. You can set the listener to bind only to the localhost interface by setting the property in ${OPENNMS_HOME}/etc/ =
  • Use firewall rules to limit access. The rules may be local to the Horizon web UI server (iptables, firewalld, or ufw), or they may be configured in a discrete external firewall that stands between the web UI and the rest of the network. Configuring these rules is beyond the scope of this section.

Restrict access to the HTTPS listener

Although HTTPS is considered secure, there are valid reasons to restrict the interfaces on which the Horizon Jetty HTTPS listener can be reached. By default, the listener is bound to all interfaces ( To bind it to a single interface, set the jetty.https-host property in ${OPENNMS_HOME}/etc/

org.opennms.netmgt.jetty.https-host =


If you encounter issues while using SSL, it might be useful to enable debug logging. You could also use one of the built-in Java system properties to configure SSL:

Property Name Description

Location of the keystore file that contains the application process’s certificate and private key.

Password to access the private key from the keystore file specified by This password is used twice: once to unlock the keystore file (store password), and once to decrypt the private key stored in the keystore (key password). The JSSE framework requires these passwords to be identical.

(Optional) Keystore type. Defaults to jks.

Location of the truststore file that contains the CA certificates that the application process trusts. If this property does not specify a truststore location, the Java implementation searches for and uses a keystore file from the following locations, in order:
* ${JAVA_HOME}/lib/security/jssecacerts * ${JAVA_HOME}/lib/security/cacerts

Password to unlock the truststore file.

(Optional) Truststore type. Defaults to jks.

(Optional) Controls logging for the SSL/TLS layer. To enable, set this property to ssl.
For more details about possible values, see debugging utilities in the official Oracle documentation.