I am encountering an issue when trying to connect to a Firebird database using the Jaybird JDBC driver with a SOCKS5 proxy. The connection works fine when connecting directly to the database without using the proxy, but when I try to use the SOCKS5 proxy, I receive the following error:

Exception in thread "main" java.sql.SQLNonTransientConnectionException: Unable to complete network request to host "localhost". [SQLState:08006, ISC error code:335544721]
	at org.firebirdsql.gds.ng.FbExceptionBuilder$Type$5.createSQLException(FbExceptionBuilder.java:677)
	at org.firebirdsql.gds.ng.FbExceptionBuilder$ExceptionInformation.toSQLException(FbExceptionBuilder.java:571)
	at org.firebirdsql.gds.ng.FbExceptionBuilder.toSQLException(FbExceptionBuilder.java:309)
	at org.firebirdsql.gds.ng.wire.WireConnection.socketConnect(WireConnection.java:298)

Caused by: java.net.SocketException: SOCKS: Connection refused
	at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:564)
	at java.net.Socket.connect(Socket.java:606)
	at org.firebirdsql.gds.ng.wire.WireConnection.socketConnect(WireConnection.java:288)

Steps to Reproduce:

• Jaybird Version: I am using Jaybird 5.0.6 for Java 8.
• Firebird Version: I am connecting to Firebird 2.5.6.
• SOCKS5 Proxy: I am running a local SOCKS5 proxy via Docker from the following image:
  Proxy Image: xkuma/socks5
• Custom Code in Jaybird: I have extended the WireConnection.java class to support SOCKS5 proxy connections. Specifically, I modified the socketConnect method to use a proxy if specified. Below is the relevant code I added to create a socket with the SOCKS5 proxy:

  protected Socket createSocket() {
      // Check if a proxy server is specified
      String proxyServerName = dbAttachInfo.getProxyServerName();
      if (proxyServerName == null || proxyServerName.isEmpty()) {
          return new Socket();  // No proxy, create a regular socket
      }
  
      // Use SOCKS proxy
      int proxyPortNumber = dbAttachInfo.getProxyPortNumber();
      return new Socket(new Proxy(Proxy.Type.SOCKS, new InetSocketAddress(proxyServerName, proxyPortNumber)));
  }