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Date:      Fri, 25 Oct 2002 20:13:41 -0700
From:      Peter Wemm <peter@wemm.org>
To:        John De Boskey <jwd@bsdwins.com>
Cc:        Current List <freebsd-current@freebsd.org>
Subject:   Re: Local DNS lookup by sshd? 
Message-ID:  <20021026031341.419932A88D@canning.wemm.org>
In-Reply-To: <20021026021753.GA95524@BSDWins.Com> 

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John De Boskey wrote:
> Hi,
> 
>    When logging into a current 5.0 system via ssh, I see the following
> written to the system console (the 'xxx's are my whiteout):
> 
> ... kernel: Connection attempt to UDP xxx.58.184.35:53 from xxx.58.184.35:492
    53
> ... kernel: Connection attempt to UDP xxx.58.184.35:53 from xxx.58.184.35:492
    54
> ... kernel: Connection attempt to UDP xxx.58.184.35:53 from xxx.58.184.35:492
    55
> ... kernel: Connection attempt to UDP xxx.58.184.35:53 from xxx.58.184.35:492
    56
> 
>    Basically, it looks like it is trying to talk to a DNS on the
> localhost. However, I do not have DNS running. I do not have localhost listed
> in /etc/resolv.conf.  /etc/nsswitch.conf lists 'hosts: files dns' and putting
> my ssh origination id in /etc/hosts has no effect.
> 
>    It appears to be related to code in canohost.c. Before I start debugging,
> I thought I'd ask if anyone knew if there is a reason for this behaviour,
> or where it might be coming from (specifically).

Are you using privsep?  If so, I think this is expected.  The unpriviliged
side runs in a chroot under /var/empty.  This means, that it cannot see any
/etc/nsswitch.conf and cannot see any /etc/resolv.conf or /etc/hosts.

And the resolver client library defaults querying on the first interface,
and in your case it used localhost.

Cheers,
-Peter
--
Peter Wemm - peter@wemm.org; peter@FreeBSD.org; peter@yahoo-inc.com
"All of this is for nothing if we don't go to the stars" - JMS/B5


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