#include <stdio.h>

#include <windows.h>




int main(int argc, char **argv)

{

  //Definitionen und Deklarationen

	int temp;

	int begin;

	int end;

	int sd;

	int loop;

	WSADATA firstsock;

	char hostname[100];

	struct sockaddr_in HOST_ADDR;



	// Input

	printf("Enter ip to scan :\t");

	gets(hostname);

	if(!(isdigit(hostname[0])))

		exit(EXIT_FAILURE);

	printf("Enter starting port :\t");

	scanf("%d" , &begin);

	printf("Enter ending port :\t");

	scanf("%d" , &end);

	system("cls");



	//Initialisiere winsock

	if (WSAStartup(MAKEWORD(2,0),&firstsock) != 0)

		{

		fprintf(stderr,"WSAStartup() failed!");

		exit(EXIT_FAILURE);

		}



	//Host definieren

	HOST_ADDR.sin_family = AF_INET;

	HOST_ADDR.sin_addr.s_addr = inet_addr(hostname);



	// Alle Daten Ausgeben und mainloop starten

	printf("Hostname:\t%s\t%d\n"

			"Startport:\t%d\n"

			"Endport:\t%d\n\n", hostname, HOST_ADDR.sin_addr.s_addr, begin, end);



	// Schleife um die einzelnen Ports abzufragen

	for(loop = begin; loop <= end; loop++)

		{

		HOST_ADDR.sin_port = htons(loop);


		//Socket öffnen

		sd = socket(AF_INET , SOCK_STREAM , IPPROTO_TCP);

		if (sd == -1)

			printf("Socket could not be created.\n");


		//Versuche mit Port zu verbinden

		temp = connect(sd , (struct sockaddr *)&HOST_ADDR , sizeof HOST_ADDR);

		if (temp == -1)

			printf("Port %d is closed.\n", loop);

		else

			printf("Port %d is open\n", loop);


		//Socket schließen

		temp = closesocket(sd);

		if (temp == -1)

			printf("Socket %s:%d could not be closed properly.\n",hostname, loop);

		}



	//Beende winsock

	WSACleanup();



	printf("Portscan has finished\n");

	system("pause");

	return EXIT_SUCCESS;

}

Pro Port braucht er eine halbe Sekunde.:upps

Was meint ihr wie kann ich den beschleunigen?

Grüße

Du könntest nonblocking sockets benutzen. Siehe WSAEventSelect.