[RESOLVED] Re: Strange resolver behavior

[Xin LI]

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JINMEI Tatuya / 神明達哉 wrote:
[snip]

At the beginning I was confused with host(1) and resolver library, they
are different problems, sorry for the confusion.

I think Hajimu-san's analysis was correct that it was caused by the
check in resolver, here is a ktrace output from a system without patched
libc:

http://www.delphij.net/kdump.txt

Note that, with a patched (with ume@'s patch) resolver, the program
*does* worked as expected, also this will make firefox to be able to
resolve the domain name.

Test program can be downloaded from http://www.delphij.net/test.c .
With patched libc you will get no output (expected), and with unpatched
libc you will get "Unknown server error" and will be unable to get the A RR.

It turns out that the baidu.com DNS administrator might be unaware of
the potential violation of RFC 952 "ASSUMPTIONS" and RFC 1034 Section
3.5.  However, I am afraid that there are some DNS server
implementations that does allow '_'s in domain names, so if there is no
potential risks allowing it from the resolver side I think it might be a
good idea to be more permissive for this case, because there are real
uses of it, and other operating systems does allow it at the client side.

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