//TCP Connect Scan

#include <stdio.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <string.h>
#include <arpa/inet.h>

int main(int argc, char* argv[])
{
    int sockfd;
    struct sockaddr_in dest_addr;
    int port = 0;
    int ret = 0;


    for(port = 1; port <= 65535; port++)
    {

    sockfd = socket(PF_INET,SOCK_STREAM,0);


    memset((char*)&dest_addr,0,sizeof(dest_addr));
    dest_addr.sin_family = AF_INET;
    dest_addr.sin_port   = htons(port);
    dest_addr.sin_addr.s_addr = inet_addr(argv[1]);


    ret = connect(sockfd,(struct sockaddr*)&dest_addr,sizeof(dest_addr));

    if(ret != -1)
        {
            printf("%d Port Open\n",port);
        }
    else
        {
            //printf("%d Port Close\n",port);
        }

    close(sockfd);
    }
printf("OK\n");

    return 0;
}



----------------------------------------------------------------------
gcc source -o File

# ./File 127.0.0.1