can't get multi-homed host address using getaddrinfo() Options

I'm using getaddrinfo("test.domain.com", NULL, &hint, &info) to
get IP addresses.

Below is /etc/hosts:
....
10.200.28.120 test.domain.com
172.0.20.120 test.domain.com
....

The problem is getaddrinfo always return only one IP address
10.200.28.120. From the man page, I think I should get a address
linked list
that mean I can get both.

Please see my demo code below:
int main()
{
struct addrinfo hints;
struct addrinfo *info;
int s;
memset((char*) &hints, '\0', sizeof(hints));
hints.ai_family = AF_INET; // just IPv4 for now
hints.ai_socktype = SOCK_STREAM; // just TCP
s = getaddrinfo("test.domain.com", NULL, &hints, &info);
if (s != 0) { printf ("error\n"); }
printf ("ok\n");
return 0;
}

I have checked info->ai_next with gdb, it's always NULL. Is there
anything wrong in my demo code? My platform it RHEL 4.0.

BTW: This demo code can get the right result on Solaris.

Thanks

Arthur

Arthur wrote:

> I'm using getaddrinfo("test.domain.com", NULL, &hint, &info) to
> get IP addresses.
>
> Below is /etc/hosts:
> ...
> 10.200.28.120 test.domain.com
> 172.0.20.120 test.domain.com
> ...
>
> The problem is getaddrinfo always return only one IP address
> 10.200.28.120. From the man page, I think I should get a address
> linked list
> that mean I can get both.
>
> Please see my demo code below:
> int main()
> {
> struct addrinfo hints;
> struct addrinfo *info;
> int s;
> memset((char*) &hints, '\0', sizeof(hints));
> hints.ai_family = AF_INET; // just IPv4 for now
> hints.ai_socktype = SOCK_STREAM; // just TCP
> s = getaddrinfo("test.domain.com", NULL, &hints, &info);
> if (s != 0) { printf ("error\n"); }
> printf ("ok\n");
> return 0;
> }
>
> I have checked info->ai_next with gdb, it's always NULL. Is there
> anything wrong in my demo code? My platform it RHEL 4.0.
>
> BTW: This demo code can get the right result on Solaris.
>
> Thanks
>
> Arthur

Can one domain have two addresses? I think that the multiple addresses that
ISPs use all have slightly different domain names (for example,
hotkey.net.au is boomer.hotkey.net.au. Another IP is frog. Something else
is duckula.) and are linked to one another. But I don't really know.

Doug.
--
Orthodoxy is my doxy; heterodoxy is your doxy.
- Wm Warburton, 18th c. Bishop of Gloucester.

Doug Laidlaw wrote:
> Arthur wrote:
>
>> I'm using getaddrinfo("test.domain.com", NULL, &hint, &info) to
>> get IP addresses.
>>
>> Below is /etc/hosts:
>> ...
>> 10.200.28.120 test.domain.com
>> 172.0.20.120 test.domain.com
>> ...
>>
>> The problem is getaddrinfo always return only one IP address
>> 10.200.28.120. From the man page, I think I should get a address
>> linked list
>> that mean I can get both.
>>
>> Please see my demo code below:
>> int main()
>> {
>> struct addrinfo hints;
>> struct addrinfo *info;
>> int s;
>> memset((char*) &hints, '\0', sizeof(hints));
>> hints.ai_family = AF_INET; // just IPv4 for now
>> hints.ai_socktype = SOCK_STREAM; // just TCP
>> s = getaddrinfo("test.domain.com", NULL, &hints, &info);
>> if (s != 0) { printf ("error\n"); }
>> printf ("ok\n");
>> return 0;
>> }
>>
>> I have checked info->ai_next with gdb, it's always NULL. Is there
>> anything wrong in my demo code? My platform it RHEL 4.0.
>>
>> BTW: This demo code can get the right result on Solaris.
>>
>> Thanks
>>
>> Arthur
>
> Can one domain have two addresses?
yes

host www.google.com
www.google.com is an alias for www.l.google.com.
www.l.google.com has address 209.85.129.147
www.l.google.com has address 209.85.129.99
www.l.google.com has address 209.85.129.104
www.google.com is an alias for www.l.google.com.


> I think that the multiple addresses that
> ISPs use all have slightly different domain names (for example,
> hotkey.net.au is boomer.hotkey.net.au. Another IP is frog. Something else
> is duckula.) and are linked to one another. But I don't really know.
>
> Doug.