Date: Tue, 12 Feb 2008 19:18:08 -0800 From: Xin LI <delphij@delphij.net> To: d@delphij.net Cc: freebsd-net@freebsd.org, Edwin Groothuis <edwin@mavetju.org>, ume@FreeBSD.org Subject: Re: Strange resolver behavior Message-ID: <47B26170.1010905@delphij.net> In-Reply-To: <47B25F71.3050005@delphij.net> References: <47B2488D.70707@delphij.net> <20080213015144.GA3957@k7.mavetju> <47B2591D.4000703@delphij.net> <20080213024643.GB3957@k7.mavetju> <47B25F71.3050005@delphij.net>
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Xin LI wrote:
> 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@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");
My bad, here should be ps_other.a.shifen.com, and the return value was
Unknown server error (NO_RECOVERY)...
> if (p == NULL)
> herror("resolve");
>
> return 0;
> }
>
>
> Cheers,
- --
Xin LI <delphij@delphij.net> http://www.delphij.net/
FreeBSD - The Power to Serve!
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