Thread: Problem with Winsock. connect() returning -1(error)

Hello,

Im trying to developing a simple portscan, but I m getting an error in the connect() function. connect() is returning -1 and I have no idea why and how to solve.

Error SS:





Before the connect() function, I have debugged and it is ok.

The code:

Code:

#include <stdlib.h>   // atoi()
#include <stdio.h>    // I/O
#include <winsock2.h> // winsock 2.0
#include <ws2tcpip.h>


#define INITIAL_PORT 1
#define FINAL_PORT 65535


int main(int argc, char* argv[])
{
   int ports,           // represents the analised port
       initialPort,     // initial port of scanning
       finalPort,       // final port of scanning
       mySocket,        // socket used for analysis of ports
       returnConnect;

   WSADATA wsaData;
   struct sockaddr_in target;    
   struct hostent *host;
   struct servent *service;

   WSAStartup(MAKEWORD(2,2),&wsaData);

   if(argc == 1)
   {
      printf("\n       ********************************************************************\n");      
      printf("       **           ScanPort v1.0 (English Version)                      **\n");    
      printf("       **                 Developed by Insurgente                        **\n");    
      printf("       **  USE  <%s> <target> <initial-port> <final-port>         **\n",argv[0]);    
      printf("       ********************************************************************\n");     

      return 0;
   }

   if(argc == 2)
   {
       initialPort = INITIAL_PORT;
       finalPort = FINAL_PORT;
   }

   if(argc > 2)
   {
      initialPort = atoi(argv[2]);
      finalPort = atoi(argv[3]);
   }

   printf("\n Scanning Ports from <%d> to <%d> in <%s>:\n",initialPort,finalPort,argv[1]);

   for(ports = initialPort; ports < finalPort; ports++)
   {
      host = gethostbyname(argv[1]);
      if (host == NULL)
      {
         printf("\nCant find Host\n");
         return 1;        
      }

      // Created to analyze the socket port
      mySocket = socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);

      if(mySocket < 0)
      {
         printf("\n\nError creating socket\n\n");
         return 1;
      }

      target.sin_family = host->h_addrtype;       // address type returned
      target.sin_port = htons(ports);            // receive the analysed port
      target.sin_addr = *((struct in_addr*)host->h_addr); //inet_addr("l0.0.2.15");
      memset(&target.sin_zero,0,sizeof(target.sin_zero));

      returnConnect = connect(mySocket,(struct sockaddr*)&target,sizeof(target));

      if(returnConnect == 0) 
      {
         printf("\nIF CONNECT()\n");
         service = getservbyport(htons(ports),"TCP");
         printf("\nPort [%d] is open. Service: [%s]",ports,(service == NULL?"Unknown":service->s_name));
         closesocket(mySocket);
      }
      else // if returnConnect == -1  then error
      {
         printf("\nELSE CONNECT()\n Error: %d,\n WSAGetLastError: %d",returnConnect,WSAGetLastError());
         closesocket(mySocket);  // if dont can to connect in port, closes the socket
      }
   }

}

If someone can help me, I thank.






Sorry for my bad english

Originally Posted by Salem

Well did you get as far as looking up what error code 10061 means?
Windows Sockets Error Codes

Thanks Salem.

Yes.

WSAECONNREFUSED10061 Connection refused. No connection could be made because the target computer actively refused it. This usually results from trying to connect to a service that is inactive on the foreign host—that is, one with no server application running.

But...this code is based in a source-code for linux, and for linux, this code runs good, showing the services running in the ports like http(80). Windows works different?






Sorry for my english

Code:

for(ports = initialPort; ports < finalPort; ports++)
{
      host = gethostbyname(argv[1]);
      if (host == NULL)
      {
         printf("\nCant find Host\n");
         return 1;        
      }

host isn't changing, so why the heck would you want to do a DNS lookup every time through the loop?

Originally Posted by Insur

Thanks Salem.

WSAECONNREFUSED10061 Connection refused. No connection could be made because the target computer actively refused it. This usually results from trying to connect to a service that is inactive on the foreign host—that is, one with no server application running.

But...this code is based in a source-code for linux, and for linux, this code runs good, showing the services running in the ports like http(80). Windows works different?

Way different!

There is another reason why ports will refuse a connection ... It's called a firewall. Even if the service is running behind the firewall, you won't get a connection to it without creating a firewall exception ... *even on your own machine *.