prlw1@newn.cam.ac.uk (Patrick Welche) wrote:

> It seems I don't understand struct hostent which has
> 
>              char    **h_addr_list;  /* list of addresses from name
>              server */
> 
> (gdb) print h->h_addr_list
> $9 = (char **) 0x48103180
[...]
> 
> In went gethostbyname2 with a host with 2 ipnumbers. Out comes the
> above. 0x7e5d3cc1 is the correct first ip number, but the second
> should look like 0xb1cc6f83 (this is on i386) but I can't see it
> anywhere! There really seems to be just the one entry in h_addr_list.
> Is that right, or am I missing something?

The following program gives me this result:

$ ./gethost pop.btx.dtag.de
Official name:  fwdallmx.t-online.com
Aliases:        pop.btx.dtag.de 
Address type:   2
Address length: 4
Address(es):    194.25.134.88 194.25.134.25 194.25.134.89 194.25.134.26
194.25.1                            
34.90 194.25.134.27 194.25.134.91 194.25.134.32 194.25.134.96
194.25.134.33 194.                            
25.134.97 194.25.134.24

gethost.c:

#include <stdlib.h>
#include <stdio.h>
#include <netdb.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

extern int h_errno;

#define ADDR_FAMILY AF_INET

int main(int argc, const char *argv[]) {
struct hostent	*hostptr;
int		i;
char	namebuf[1024];

 if (argc < 2) {
	fprintf(stderr, "usage: gethost HOSTNAME\n");
 	return EXIT_FAILURE;
 }

 hostptr = gethostbyname2(argv[1], ADDR_FAMILY);
 
 if (hostptr == NULL) {
 	herror("gethostbyname2() failed");
 	return EXIT_FAILURE;
 }
 
 printf("Official name:  %s\n", hostptr->h_name);
 printf("Aliases:        ");
 
 	for(i = 0; hostptr->h_aliases[i] != NULL; i++) 
 		printf("%s ", hostptr->h_aliases[i]);
 
 printf("\n");
 printf("Address type:   %d\n", hostptr->h_addrtype);
 printf("Address length: %d\n", hostptr->h_length);
 printf("Address(es):    ");

 	for(i = 0; hostptr->h_addr_list[i] != NULL; i++) 
	{
 		printf("%s ",	inet_ntop(	ADDR_FAMILY, 
									hostptr->h_addr_list[i], 
									namebuf, 
									sizeof(namebuf) - 1));
	}	
 
 printf("\n");
 return EXIT_SUCCESS;
}

-------------

Therefore, I don't really see your problem. What do nslookup and
dnsquery tell you? Maybe there's some problem with the local or remote
DNS configuration.

Michael