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Re: what is the static ip address I assigned to eth0?

From Reco <recoverym4n@gmail.com>
Newsgroups linux.debian.user
Subject Re: what is the static ip address I assigned to eth0?
Date 2015-08-31 09:00 +0200
Message-ID <q3rep-5o-11@gated-at.bofh.it> (permalink)
References (6 earlier) <q2pHI-1s8-35@gated-at.bofh.it> <q2qkq-2bz-13@gated-at.bofh.it> <q2s2T-4H9-7@gated-at.bofh.it> <q2svU-5uI-19@gated-at.bofh.it> <q3kPD-7SX-1@gated-at.bofh.it>
Organization linux.* mail to news gateway

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 Hi.

On Sun, 30 Aug 2015 19:00:55 -0500
David Wright <deblis@lionunicorn.co.uk> wrote:

> Quoting Reco (recoverym4n@gmail.com):
> > On Fri, 28 Aug 2015 14:35:09 +0100
> > Brian <ad44@cityscape.co.uk> wrote:
> > > On Fri 28 Aug 2015 at 14:45:32 +0300, Reco wrote:
> > > > On Fri, 28 Aug 2015 12:09:08 +0100
> > > > Brian <ad44@cityscape.co.uk> wrote:
> > > > > On Fri 28 Aug 2015 at 10:01:59 +0000, Curt wrote:
> > > > > > On 2015-08-28, David Wright <deblis@lionunicorn.co.uk> wrote:
> > > > > > >
> > > > > > > $ host localhost
> > > > > > > Host localhost not found: 3(NXDOMAIN)
> > > > > > > $ ping localhost
> > > > > > > PING localhost (127.0.0.1) 56(84) bytes of data.
> > > > > > > 64 bytes from localhost (127.0.0.1): icmp_req=1 ttl=64 time=0.032 ms
> > > > > > 
> > > > > > curty@einstein:~$ host localhost
> > > > > > localhost has address 127.0.0.1
> > > > > > localhost has IPv6 address ::1
> > > > > 
> > > > > To complete the picture:
> > > > > 
> > > > >   brian@desktop:~$ dig -x 127.0.0.1
> > > > > 
> > > > >   ; <<>> DiG 9.9.5-9-Debian <<>> -x 127.0.0.1
> [...]
> > > > >   ;; ANSWER SECTION:
> > > > >   1.0.0.127.in-addr.arpa. 10800   IN      PTR     localhost.
> [...]
> > > > > host and dig use only the DNS.
> > > > > 
> > > > > Elimar's suggestion to use 'host $(hostname)' will work if hostname is
> > > > > a FQDN. But it shouldn't (or wouldn't) be on a stock Debian system.
> > > > 
> > > > Not unless said 'stock Debian system' has 'search <domain>' stanza
> > > > in /etc/resolv.conf.
> > > 
> > > Does "search example.org" count? :)
> > 
> > It should count for the hosts in this domain. Provided, of course, that
> > one needs to resolve 'bare' hostnames (i.e. non-FQDN).
> > 
> > > What is not understandable (to me) is why 'host localhost' resolves for
> > > some but not for others and why it is thought 'host $(hostname)' should
> > > resolve in the DNS.
> > 
> > Stock Debian BIND configuration includes this wonderful snippet
> > (/etc/bind/db.local):
> > 
> > ;
> > ; BIND data file for local loopback interface
> > ;
> > $TTL    604800
> > @       IN      SOA     localhost. root.localhost. (
> >                               2         ; Serial
> >                          604800         ; Refresh
> >                           86400         ; Retry
> >                         2419200         ; Expire
> >                          604800 )       ; Negative Cache TTL
> > ;
> > @       IN      NS      localhost.
> > @       IN      A       127.0.0.1
> > @       IN      AAAA    ::1
> > 
> > Translating this to English - every BIND installed on Debian considers
> > itself the final authority on "localhost" zone and always returns
> > 127.0.0.1 for A queries (IPv4) and ::1 for AAAA queries (IPv6).
> > Other Linux distributions can store zone files elsewhere, but the
> > principle is the same.
> > Interpreting /etc/bind/db.127 (PTR entries) is left for an exercise for
> > the readers.
> > 
> > So - 'host localhost' *should* work given an ideal world (because in
> > ideal world everyone will use an ideal DNS, which is BIND).
> 
> Why on earth would I want to use BIND on my LAN at home? Just so I
> have to read and understand RFC1035? No, I just put the hostnames
> and addresses into /etc/hosts. (And script it because I have five
> to do.)

If you have one PC and one router - BIND is redundant indeed (although
useful to combat those pesky NXDOMAIN hijackers). Once the number of PCs
(tablets, phones, whatever) grows, the need of DNS usually comes by
itself.


> Debian correctly puts   127.0.0.1 localhost   into /etc/hosts and
> hosts: files mdns4_minimal [NOTFOUND=return] dns
> into /etc/nsswitch.conf. So it's the hosts file that resolves
> localhost. DNS is not involved. BIND has to know the answer *in case*
> it's asked, not because it's *got to be* asked.

Assuming that you use the sane software which respects nsswitch.conf -
that's true. Sadly, not all software is sane (and no, I'm not meaning
dig, nslookup and host).
Also, *your* nsswitch.conf clearly shows that your are:

1) Using mDNS for name resolution (and it can complicate things with
it's .local domain).

2) Definitely allowing the host to use DNS :)


> My earlier posting (included above) was to show that, of the many
> suggestions made in this thread, "host" was not a good choice on a
> typical correctly-configured system.

That's true indeed. On a local host "ifconfig" or "ip a" is more than
enough.

Reco

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Thread

what is the static ip address I assigned to eth0? rlharris@oplink.net - 2015-08-27 09:10 +0200
  [solved] Re: what is the static ip address I assigned to eth0? rlharris@oplink.net - 2015-08-27 09:30 +0200
    Re: [solved] Re: what is the static ip address I assigned to eth0? Jörg-Volker Peetz <jvpeetz@web.de> - 2015-08-27 12:50 +0200
  Re: what is the static ip address I assigned to eth0? Gene Heskett <gheskett@wdtv.com> - 2015-08-27 10:30 +0200
    Re: what is the static ip address I assigned to eth0? Renaud (Ron) OLGIATI <renaud@olgiati-in-paraguay.org> - 2015-08-27 12:10 +0200
      Re: what is the static ip address I assigned to eth0? Hans <hans.ullrich@loop.de> - 2015-08-27 12:30 +0200
        Re: what is the static ip address I assigned to eth0? David Wright <deblis@lionunicorn.co.uk> - 2015-08-27 20:40 +0200
      Re: what is the static ip address I assigned to eth0? "Thomas Schmitt" <scdbackup@gmx.net> - 2015-08-27 12:30 +0200
      Re: what is the static ip address I assigned to eth0? Gene Heskett <gheskett@wdtv.com> - 2015-08-27 18:10 +0200
  Re: what is the static ip address I assigned to eth0? Elimar Riesebieter <riesebie@lxtec.de> - 2015-08-27 12:00 +0200
    Re: what is the static ip address I assigned to eth0? David Wright <deblis@lionunicorn.co.uk> - 2015-08-27 20:40 +0200
      Re: what is the static ip address I assigned to eth0? Elimar Riesebieter <riesebie@lxtec.de> - 2015-08-28 01:00 +0200
        Re: what is the static ip address I assigned to eth0? David Wright <deblis@lionunicorn.co.uk> - 2015-08-28 06:40 +0200
          Re: what is the static ip address I assigned to eth0? Curt <curty@free.fr> - 2015-08-28 12:10 +0200
            Re: what is the static ip address I assigned to eth0? Brian <ad44@cityscape.co.uk> - 2015-08-28 13:10 +0200
              Re: what is the static ip address I assigned to eth0? Reco <recoverym4n@gmail.com> - 2015-08-28 13:50 +0200
                Re: what is the static ip address I assigned to eth0? Brian <ad44@cityscape.co.uk> - 2015-08-28 15:40 +0200
                Re: what is the static ip address I assigned to eth0? Reco <recoverym4n@gmail.com> - 2015-08-28 16:10 +0200
                Re: what is the static ip address I assigned to eth0? Brian <ad44@cityscape.co.uk> - 2015-08-28 16:50 +0200
                Re: what is the static ip address I assigned to eth0? Curt <curty@free.fr> - 2015-08-28 18:20 +0200
                Re: what is the static ip address I assigned to eth0? Brian <ad44@cityscape.co.uk> - 2015-08-28 18:40 +0200
                Re: what is the static ip address I assigned to eth0? David Wright <deblis@lionunicorn.co.uk> - 2015-08-31 02:10 +0200
                Re: what is the static ip address I assigned to eth0? Reco <recoverym4n@gmail.com> - 2015-08-31 09:00 +0200
                Re: what is the static ip address I assigned to eth0? David Wright <deblis@lionunicorn.co.uk> - 2015-08-30 05:10 +0200

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