是否必须写入套接字才能让服务器向我发送读取响应以获取某些服务的横幅？

Question

public class PortScan 
{

public String ip;

public PortScan(String ip)
{
    this.ip = ip;
}
public void setIP( String ip )
{
    this.ip = ip;   
}

public String getIP()
{
    return this.ip;
}
public void scan()
{
    int i = 1;
    String ip = this.getIP();
    while(i < 50000)
    {
    try
    {
        Socket sock = new Socket(ip, i);
        InputStream in = sock.getInputStream();
        OutputStream out = sock.getOutputStream();
        BufferedInputStream bins = new BufferedInputStream(in);
        BufferedReader bin = new BufferedReader(new InputStreamReader(bins));
        String response = bin.readLine();
        System.out.println(response);
        System.out.println(ip + ":" + i);
        sock.close();
    }
    catch( UnknownHostException e )
    {

        //System.out.println("No host found.");
    }
    catch(IOException e)
    {

        //System.out.println("Problem connection to host.");
    }
    i++;
    }
} 
public static void main(String[] args) 
{
    PortScan aPortScan = new PortScan("127.1.1.1");

    aPortScan.scan();
}
}

控制台输出：

SSH-2.0-OpenSSH_6.0p1 Debian-4
127.1.1.1:22<
null
127.1.1.1:80

Answer 1

是的，有些服务需要交互才能输出横幅。对于HTTP服务器，您必须发送GET / HTTP/1.1，然后解析Server:行的响应。