Running Unimus behind a HTTP(S) proxy is fully supported, but requires additional configuration.

On Windows:

For installer:
Create a file named Unimus.l4j.ini in 'C:\Program Files\Unimus\'.

For portable:
Create a file named Unimus.l4j.ini in the same directory as the Unimus executable.
Change Unimus in the above file name to exactly match the name of the Unimus executable.

Inside of this configuration file, please place the following lines:

-Dhttp.proxyHost=1.1.1.1
-Dhttp.proxyPort=8080
-Dhttps.proxyHost=2.2.2.2
-Dhttps.proxyPort=8443

Please make sure to place each argument into its own line.
Insert proper values behind each configuration argument.

If you only use HTTP proxy, or only use HTTPS proxy, remove the other from the configuration file

Restart Unimus, and any HTTP(S) outbound connectivity from Unimus will go through the configured proxy.

On Linux (Debian/Ubuntu):

Edit the contents of /etc/init.d/unimus.
Change the following:

# Optional arguments to start Unimus with
ARGS="-Dhttp.proxyHost=1.1.1.1 -Dhttp.proxyPort=8080 -Dhttps.proxyHost=2.2.2.2 -Dhttps.proxyPort=8443"

Insert proper values behind each configuration argument.

If you only use HTTP proxy, or only use HTTPS proxy, remove the other from the configuration file

Restart Unimus, and any HTTP(S) outbound connectivity from Unimus will go through the configured proxy.

Running in Tomcat:

Please refer to Tomcat documentation on configuring proxying.

How this is configured depends on the distribution and packaging of your Tomcat.