Re: Temporary failure in name resolution

From	Greg Wooledge <greg@wooledge.org>
Newsgroups	linux.debian.user
Subject	Re: Temporary failure in name resolution
Date	2021-04-03 19:00 +0200
Message-ID	<BZRMS-1sf-3@gated-at.bofh.it> (permalink)
References	<BZRjP-1hY-7@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Sat, Apr 03, 2021 at 12:05:54PM -0400, Dan Norton wrote:
> On 3/31/21 1:33 PM, David Christensen wrote:
> 
> "$ host -v -t A www.debian.org 192.168.1.254
> 
> 
> Dan -- did you run the above test? This may help isolate if the problem
> is Debian 10 or your AT&T gateway."
> 
> $ host -v -t A www.debian.org 192.168.1.254
> Trying "www.debian.org"
> ;; connection timed out; no servers could be reached
> 
> That's to be expected I guess since nameserver 192.168.1.254 is no
> longer in resolv.conf.

*facepalm*

I don't understand what you don't understand.  It's so frustrating.

When you do a command like

  host www.debian.org

This uses the "nameserver" line(s) in resolv.conf to decide where to
send the requests.

When you OVERRIDE THIS WITH AN IP ADDRESS ON THE COMMAND LINE, it uses
that IP address as the nameserver (recursive resolver) instead.

SYNOPSIS
       host  [-aACdlnrsTUwv]  [-c  class] [-N ndots] [-p port] [-R number] [-t
       type] [-W wait] [-m flag] [ [-4] | [-6] ] [-v] [-V] {name} [server]

       [...]

       server is an optional argument which is either the name or  IP  address
       of  the  name  server  that  host should query instead of the server or
       servers listed in /etc/resolv.conf.

See there?  You've specified a {name} (www.debian.org) and an optional
[server] (192.168.1.254).  Therefore it uses that instead of whatever
is written in resolv.conf.

The entire point of running this command was to probe the nameserver
at 192.168.1.254 and see whether it's working correctly.

> $ host -v -t A www.debian.org 192.168.1.254
> Trying "www.debian.org"
> ;; connection timed out; no servers could be reached

It's not working correctly.  Now you know.

Thread

Re: Temporary failure in name resolution Dan Norton <dnorton@mindspring.com> - 2021-04-03 18:30 +0200
  Re: Temporary failure in name resolution Greg Wooledge <greg@wooledge.org> - 2021-04-03 19:00 +0200
  Re: Temporary failure in name resolution David Christensen <dpchrist@holgerdanske.com> - 2021-04-03 23:30 +0200

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