Gerd Wagner - 2020-12-15

Sorry, I don't have the chance to test a JDBC connection via a proxy myself.

If you know a bit of Java you could try out the following:
Configure your proxy using
java.lang.System.getProperties().put("proxySet", "true");
java.lang.System.getProperties().put("http.proxyHost", "<yourproxyhost>");
java.lang.System.getProperties().put("http.proxyPort", "<yourproxyport>");
java.lang.System.getProperties().put("http.nonProxyHosts", "<yournonproxyhosts>");
java.lang.System.getProperties().put("http.proxyPort", "<yourproxyport>");
java.lang.System.getProperties().put("http.nonProxyHosts", "<yournonproxyhosts>");</yournonproxyhosts></yourproxyport></yournonproxyhosts></yourproxyport></yourproxyhost>

and if you use SOCKS Proxy
java.lang.System.getProperties().put("socksProxyHost", "<yoursocksproxyhost>");
java.lang.System.getProperties().put("socksProxyPort", "<yoursocksproxyport>");</yoursocksproxyport></yoursocksproxyhost>

Then try to open a JDBC connection to your database. If this doesn't work either the problem is not due to SQuirreL.