For information about why to customize the EDH key size, see Section 6.6, Customizing the Size of Ephemeral Diffie-Hellman Keys.
Open the /opt/novell/nam/adminconsole/conf/tomcat7.conf file.
Ensure that the following lines exist:
JAVA_OPTS="${JAVA_OPTS} -Djdk.tls.ephemeralDHKeySize=2048"