Send a request using Http(s)URLConnection through proxy issue

Question

Hi all,
Here are system environment,
OS: Ubuntu 12.04
Java version: 1.6.0_27
OpenJDK Runtime Environment (IcedTea6 1.12.4) (6b27-1.12.4-1ubuntu1)
OpenJDK 64-Bit Server VM (build 20.0-b12, mixed mode)
There are 3 roles introduction as below:
1. A https client: It can not direct connect to https server. Because it is restricted in a enclosed network environment just like intranet(ip is 10.100.11.8).The only way out is proxy server.
2. A proxy server: Locate between https client and https server. It have two network interfaces(ip are 10.100.11.10 and 192.168.11.10)
3. A https server: It is on extranet(ip is 192.168.11.123) and it also cannot connect to https client directly.
The other network environment setup is: There is no DNS server on https client network environment.
The following is part of https client code section:
        public static void main(String args[]){
           String proxyIp ="10.100.11.10";// proxy server IP
           testConn(proxyIp);
        private static void testConn(String proxyIp){
                String httpsURL="https://192.168.11.123:8443/httpsServices";
                setSSLContext();// I thought this is not root cause so I do not post on
                try{
                  InetAddress intIPAdd= InetAddress.getByAddress(convStrToByte(proxyIp));
                  InetSocketAddress proxyInetAddr = new InetSocketAddress(intIPAdd,80);
                  Proxy proxy = new Proxy(Proxy.Type.HTTP, proxyInetAddr);
                  URL httpsUrl = new URL(httpsURL);
                  HttpsURLConnection httpsCon = (HttpsURLConnection) httpsUrl.openConnection(proxy);
                  httpsCon.setDoOutput(true);
                  httpsCon.setDoInput(true);
                  httpsCon.setRequestMethod("POST");
                  httpsCon.setDefaultUseCaches(true);   
                  httpsCon.setUseCaches(true);
                  System.out.println("Get OutPutStream start!");
                  OutputStream out = httpsCon.getOutputStream(); // or httpsCon.connect();
                  System.out.println("Get OutPutStream done!");
                  OutputStreamWriter owriter = new OutputStreamWriter(out);
                  owriter.write("<request>test</request>");
                  owriter.flush();
                  owriter.close();
        private static byte[]  convStrToByte(String ip){
        String str[] = ip.split("\\.");
        byte[] ipAry = new byte[str.length];
          for(int i=0;i<str.length;i++){
            ipAry[i] = (byte) Integer.parseInt(str, 10);
return ipAry;
All right, my problem is, while print out "Get OutPutStream start" untill "Get OutPutStream done", it always takes about 5 secs.
No Error or exception. It was just hanging there approx 5 secs.
I observed the packets flow with wireshark.
Found out that hang time is to send a multicast to ask MDNS the proxy IP. No one reply this message. It would ask 3 times and then send request to proxy.
About https trust and authentication issue. I use *All Trust* solution. because https server use self-signed CA by myself.
If need, I would update this post with code section of setSSLContext() part.
I wondering to know that I create proxy object using *InetSocketAddress(InetAddress addr, int port)*, or I create proxy ip instance using *public static InetAddress getByAddress(byte[] addr)* why it would ask to MDNS for proxy ip?
On normal concept, I give an ip address and it do not need to resolve this ip for domain name.
Check InetAddress getByAddress(byte[] addr) of JAVA SE6 API:
It says: 'This method doesn't block, i.e. no reverse name service lookup is performed.'
What can I do to let https client don't need to ask MDNS?
Thank you guys so much.
Edited by: 1002346 on 2013/4/29 上午 12:05                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       

Answer 1

Java does reverse DNS lookups for security reasons. Not sure you can disable it but if you can it will be described on the Networking Properties page.