Here’s the key:
add the proxy configs to catalina.properties, just at the end, one per line. This is only mentioned in the Confluence-proxy article I found, but it works with Jira as well. Much cleaner.
/opt/atlassian/confluence/conf/catalinia.properties. Here’s what I added to the end of that file:
# Proxy Settings
NOTE: that nonProxyHosts doesn’t *seem* to work with wildcards, e.g. 10.*.*.*
When I did it this way I could never get Confluence to actually connect to Jira and Jira to connect to Confluence. You have to specify the entire IP address. Otherwise, you’ll get messages about “connection refused” or “the application doesn’t appear to be online”. Not very helpful at all, no sir.