strange resolver behavour

[Hajimu UMEMOTO]

Hi,

>>>>> On Mon, 11 Oct 2010 13:31:04 +0700
>>>>> Eugene Grosbein <egrosbein at rdtc.ru> said:

egrosbein> FreeBSD 8.1-STABLE:

egrosbein> # host koin-nkz.com.
egrosbein> koin-nkz.com has address 62.231.164.101
egrosbein> Host koin-nkz.com not found: 3(NXDOMAIN)

egrosbein> This domain does not have MX records but NXDOMAIN seems to wrong return
egrosbein> code to me. Think about MTA that does look-up for MX first,
egrosbein> obtains NXDOMAIN and rejects mail.

egrosbein> tcpdump shows that after MX look-up failure resolver adds my local
egrosbein> domain suffix from /etc/resolv.conf's "search" clause and
egrosbein> goes to my local DNS server looking for MX record for
egrosbein> 'koin-nkz.com.my.ru.' that does not exists. Hence, NXDOMAIN.

egrosbein> Is it a bug in our resolver?

I think no, host(1) links ISC's resolver, and it doesn't use libc's
resolver.  I suspect there is some problem in host(1) or ISC's
resolver.

egrosbein> I've tested 6.4-STABLE and 7.3-STABLE, same effect.
egrosbein> I've also tested 4.11-STABLE and it works correctly - no wrong
egrosbein> suffix addition, no NXDOMAIN.

4.X's host(1) is from BIND8, but it comes from BIND9 on 5.X and later.
I confirmed it on my 4.11 box with our in-tree host(1).  However,
host(1) from ports has same behavior with 8.1.  It is bind9-9.3.6.1.1.

% uname -r
4.11-RELEASE-p25
% /usr/bin/host koin-nkz.com.
koin-nkz.com has address 62.231.164.101
% /usr/local/bin/host koin-nkz.com.
koin-nkz.com has address 62.231.164.101
Host koin-nkz.com not found: 3(NXDOMAIN)

Sincerely,

--
Hajimu UMEMOTO @ Internet Mutual Aid Society Yokohama, Japan
ume at mahoroba.org  ume@{,jp.}FreeBSD.org
http://www.imasy.org/~ume/