How to send dns packet?

[Umar Ali]

Hello

I want to send a dns packet to a dns server. I've already connected to the dns server but not able to send the packet in the right wy. Actually I don't know how to send? Here's the code..

#include <winsock.h>
#include<stdio.h>
#include<string.h>
#include <io.h>
#include <sys/stat.h>

int main()
{
	
	WSADATA wsaData;
	if (WSAStartup(MAKEWORD(1, 1), &wsaData) != 0) {
		fprintf(stderr, "WSAStartup failed.\n");
		exit(1);
	}

	int sock;
	struct sockaddr_in serv_addr;

	sock = socket(AF_INET,SOCK_DGRAM,0);
	
	if(sock == -1){
		printf("Error creating socket");
	}

	serv_addr.sin_family = AF_INET;
	serv_addr.sin_port = htons(53);
	serv_addr.sin_addr.s_addr = inet_addr("208.67.222.222");//Notice that inet_addr() returns the address in Network Byte Order already–you don’t have to call htonl()
	//bzero(&(serv_addr.sin_zero),8);

	int i= connect(sock, (struct sockaddr*)& serv_addr, sizeof(struct sockaddr));	
	if(i==-1) {
		printf("nahhhhh");
	}
	else{
		printf("Connection Established\n");
	
	}
	char *send_data, recv_data[1024];
	send_data="00020100000100000000000003706F7064026978066E6574636F6D03636F6D0000010001"; //dns header and dns messages concatinated
	printf("send_data is: %s\n", send_data);
	send(sock, send_data, strlen(send_data), 0); // send data to server
		
	if(strcmp(send_data, "EXIT") == 0) {
		printf("%s", "Disconnected!\n\n");
		//break;
	}


	int byte_count = recv(sock,recv_data,1024,0); // receive data from server
	recv_data[byte_count] = '\0';

	printf("Recieved data is: %s",recv_data);
		
	closesocket(sock);

	return 0;

}

Kindly help me out...
Regards

[Ancient Dragon]

That code is already sending something on line 41.

[Umar Ali]

Hello

I want to send a dns packet to a dns server. I've already connected to the dns server but not able to send the packet in the right wy. Actually I don't know how to send? Here's the code..

#include <winsock.h>
#include<stdio.h>
#include<string.h>
#include <io.h>
#include <sys/stat.h>

int main()
{
	
	WSADATA wsaData;
	if (WSAStartup(MAKEWORD(1, 1), &wsaData) != 0) {
		fprintf(stderr, "WSAStartup failed.\n");
		exit(1);
	}

	int sock;
	struct sockaddr_in serv_addr;

	sock = socket(AF_INET,SOCK_DGRAM,0);
	
	if(sock == -1){
		printf("Error creating socket");
	}

	serv_addr.sin_family = AF_INET;
	serv_addr.sin_port = htons(53);
	serv_addr.sin_addr.s_addr = inet_addr("208.67.222.222");//Notice that inet_addr() returns the address in Network Byte Order already–you don’t have to call htonl()
	//bzero(&(serv_addr.sin_zero),8);

	int i= connect(sock, (struct sockaddr*)& serv_addr, sizeof(struct sockaddr));	
	if(i==-1) {
		printf("nahhhhh");
	}
	else{
		printf("Connection Established\n");
	
	}
	char *send_data, recv_data[1024];
	send_data="00020100000100000000000003706F7064026978066E6574636F6D03636F6D0000010001"; //dns header and dns messages concatinated
	printf("send_data is: %s\n", send_data);
	send(sock, send_data, strlen(send_data), 0); // send data to server
		
	if(strcmp(send_data, "EXIT") == 0) {
		printf("%s", "Disconnected!\n\n");
		//break;
	}


	int byte_count = recv(sock,recv_data,1024,0); // receive data from server
	recv_data[byte_count] = '\0';

	printf("Recieved data is: %s",recv_data);
		
	closesocket(sock);

	return 0;

}

Kindly help me out...
Regards

Well I checked my packet from wireshark, it say that it's malform packet.. I want to ask, what should be the right syntax to send the dns packet. I didn't make my code generic thus far, just put the data in send data (hard code). Kindly reason out...