Can't access any website via proxy chain (Java exception is thrown)

[Daniel Hochheimer]

Hi,

For a project I'm working on, I need to connect to targets via an HTTP(S) proxy (with HTTP authentication).

I've configured ZAP to use this proxy server (via the 'Connection' settings).

However, if I open a browser via ZAP, and open any URL, I get the following error message:

```

ZAP Error [java.net.ConnectException]: Connection refused (Connection refused) Stack Trace: java.net.ConnectException: Connection refused (Connection refused) at java.base/java.net.PlainSocketImpl.socketConnect(Native Method) at java.base/java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:399) at java.base/java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:242) at java.base/java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:224) at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392) at java.base/java.net.Socket.connect(Socket.java:609) at org.zaproxy.zap.ZAP$ProtocolSocketFactoryImpl.createSocket(ZAP.java:434) at org.apache.commons.httpclient.HttpConnection.open(HttpConnection.java:728) at org.apache.commons.httpclient.MultiThreadedHttpConnectionManager$HttpConnectionAdapter.open(MultiThreadedHttpConnectionManager.java:1361) at org.apache.commons.httpclient.HttpMethodDirector.executeWithRetry(HttpMethodDirector.java:457) at org.apache.commons.httpclient.HttpMethodDirector.executeMethod(HttpMethodDirector.java:207) at org.apache.commons.httpclient.HttpClient.executeMethod(HttpClient.java:397) at org.parosproxy.paros.network.HttpSender.executeMethod(HttpSender.java:429) at org.parosproxy.paros.network.HttpSender.runMethod(HttpSender.java:671) at org.parosproxy.paros.network.HttpSender.send(HttpSender.java:626) at org.parosproxy.paros.network.HttpSender.sendAuthenticated(HttpSender.java:601) at org.parosproxy.paros.network.HttpSender.sendAuthenticated(HttpSender.java:584) at org.parosproxy.paros.network.HttpSender.sendAndReceive(HttpSender.java:489) at org.parosproxy.paros.network.HttpSender.sendAndReceive(HttpSender.java:459) at org.parosproxy.paros.core.proxy.ProxyThread.processHttp(ProxyThread.java:562) at org.parosproxy.paros.core.proxy.ProxyThread.run(ProxyThread.java:319) at java.base/java.lang.Thread.run(Thread.java:829)

```

This exception is displayed in the browser, not on the command line.

'zap.log' doesn't seem to contain any useful information for debugging this.

On my phone I can connect to the target via the required proxy without a problem.

I tried to configure the proxy settings in ZAP with and without login data (on my phone, no login data are required for the proxy setup, and the browser asks for them).

For 'realm' I used the proxy domain, or I left it empty.

Does anybody know what the problem could be, and how to overcome it?

Best regards,

Daniel