Strange resolver behavior

[Xin LI]

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Edwin Groothuis wrote:
> On Tue, Feb 12, 2008 at 06:42:37PM -0800, Xin LI wrote:
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>> Edwin Groothuis wrote:
>>> On Tue, Feb 12, 2008 at 05:31:57PM -0800, Xin LI wrote:
>>>> Received 127 bytes from 127.0.0.1#53 in 0 ms
>>>> [delphij at charlie] ~> host ps_other.a.shifen.com
>>>> ps_other.a.shifen.com has address 202.108.22.46
>>>> Host ps_other.a.shifen.com not found: 3(NXDOMAIN)
>>> 12:49:45.620015 IP 10.251.1.18.51852 > 202.108.22.102.53:  18450 MX? ps_other.a.shifen.com. (39)
>>> 12:49:46.086227 IP 202.108.22.102.53 > 10.251.1.18.51852:  18450 NotImp*- 0/0/0 (39)
>>>
>>> That's the one it is complaining about, not about the hostname
>>> itself.
>>>
>>> Yes, the warning/error message could be a little bit smarter.
>> Em...  That's fine I think, it does not seem to be the MX to cause the
>> problem, though.  I have tried to visit 'dict.baidu.com' in Firefox and
>> it told me that the name can not resolve.  tcpdump indicates that the
>> server has respond the A RR but resolver still queries AAAA...
> 
> Yes, but it is the MX record querying it is complaining about.

Well, so perhaps that they are different problems?

What I think is a problem is that attempting to resolve
'ps_other.a.shifen.com' gets "Unknown host", here is a quick testcase:

#include <netdb.h>
#include <stdio.h>

int
main(void)
{
	struct hostent *p;

	p = gethostbyname("ps_other.shifen.com");
	if (p == NULL)
		herror("resolve");

	return 0;
}


Cheers,
- --
Xin LI <delphij at delphij.net>	http://www.delphij.net/
FreeBSD - The Power to Serve!
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