android - Socket Connection always returns true even if Port is not open (Port Scan) -

question:

i have for statement, calls method different ip addresses (ranging 10.0.0.1 10.0.0.255 because don't have ip scanner). method future callable , returns boolean true or false. function of method make socket, connect socket given ip & port + timeout, , return true or false based on if given ip address, has port open or not.

my plan: i'm trying check if device connected same wifi network has open port (ssh port) can ssh device without knowing it's ip-address. idea private ip-address of android device, check if equal common private ip-address (for example 10.0.0.*) , scan it's ip-range (from 10.0.0.1-255) open ssh port (22).

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todo:

1. get ip android device (checked)
2. filter it, if private ip starting "10." && "10.0.0." or "192." && "192.168." , on (checked)
3. check if port 22 open or not on range "10.0.0.1-255" or "192.168.1.1-255". (current)

i used code here port scanner: socket port scanner in question future method returned true or false if port on fixed ip-address open or not. result of method added future boolean list array. queried, user see how many ports open on fixed ip-address.

i modified method scanning number of ip-addresses fixed port, , adding ip-addresses, ssh port open, future boolean list array. works except socket.connect(new inetsocketaddress(ip, port), timeout); returns true. tried looking @ code why that, found no answers. if have idea how have socket return false, when given port on ip address not open, please let me know. in advance.

code:

here call socket method (portisopen) , if returns true, append ip adress sent method stringbuilder possibleipaddresses. way can list ip-addresses have port open , later connect them.

//initialisiert variablen für den port prüfer public stringbuilder possibleipaddress = new stringbuilder(""); final executorservice es = executors.newfixedthreadpool(50); final int timeout = 500; final list<future<boolean>> futures = new arraylist<>();  //code querying ip adress here.  //checking ip-addresses 10.0.0.1-10.0.0.255 open ssh port string ip = ""; (int x=1;x<=10;x++) {     ip = "10.0.0."+x;      //should return true if port on ip-address open, returns true everytime..help?     if (futures.add(portisopen(es, ip, 22, timeout))) {         possibleipaddress.append(ip).append("\n");     }      es.shutdown();  } 

and here code port scanner (it same in port scanner question)

public static future<boolean> portisopen(final executorservice es, final string ip, final int port, final int timeout) {     return es.submit(new callable<boolean>() {         @override public boolean call() {             try {                 socket socket = new socket();                 socket.connect(new inetsocketaddress(ip, port), timeout);                 socket.close();                 return true;             } catch (exception ex) {                 return false;             }         }     }); } 

your portisopen() method returns future, result never getting, method never returns @ all, because never called. need add list of possible ip addresses if , if result of future true.

nb you're leaking sockets in case there exception. use try-with-resources syntax fix that.