Re: How to resolve names

Norbert Kolvenbach <noko4711@xxxxxxxxxxx> writes:

Ian Northeast wrote:

On Sun, 18 Mar 2007 17:56:35 +0100, Norbert Kolvenbach wrote:

Dear experts,

this is possibly a very dumb problem/question and that may be the reason
I do not get a resolution.

i have 3 Linux pc connected to the internet via WLAN DSL router. 2 are
conencted via WLAN one is directly connected via LAN cable. The router
uses DHCP to assign dynamic IP addresses.

So I can ping and try to ssh/telnet the 2 other machines from my PC via
ip-address (no supprise).

I cannot do it by using their host names although I get proper
name/address resolution via nslookup.

What is in your /etc/resolv.conf? What does route -n say?



As it stands this doesn't add up. If ping etc. by IP works and nslookup of
the names works (nslookup is a broken and outdated tool BTW, you should
use dig instead, but its brokenness does not extend to returning answers
when none are available) then ping etc. by name should too.

I assume that the router is acting as the DNS server, can you confirm
this?

Yes. Router is DNS and DHCP server


What output/errors are issued when you:

ping <name>

ping: unknown host <name>


dig <name>
~> dig <name>

; <<>> DiG 9.3.2 <<>> debach
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 5425
;; flags: qr aa ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;debach. IN A

;; ANSWER SECTION:
<name>. 10 IN A 192.168.2.101

;; Query time: 1 msec
;; SERVER: 192.168.2.1#53(192.168.2.1)
;; WHEN: Mon Mar 19 17:48:01 2007
;; MSG SIZE rcvd: 46


host <name>
~> host <name>
<name> has address 192.168.2.101
Host <name> not found: 3(NXDOMAIN)
Host <name> not found: 3(NXDOMAIN)


getent hosts <name>

~>getent hosts <name>
~>
zero oputput!



Note that dig does not append the domain name specified in
/etc/resolv.conf, you have to include it in the command, i.e. dig
<host>.<domain>.

what is in /etc/resolv.conf?

cat /etc/resolv.conf
### BEGIN INFO
#
# Modified_by: dhcpcd
# Backup: /etc/resolv.conf.saved.by.dhcpcd.eth0
# Process: dhcpcd
# Process_id: 2644
# Script: /sbin/modify_resolvconf
# Saveto:
# Info: This is a temporary resolv.conf created by service dhcpcd.
# The previous file has been saved and will be restored later.
#
# If you don't like your resolv.conf to be changed, you
# can set MODIFY_{RESOLV,NAMED}_CONF_DYNAMICALLY=no. This
# variables are placed in /etc/sysconfig/network/config.
#
# You can also configure service dhcpcd not to modify it.
#
# If you don't like dhcpcd to change your nameserver
# settings
# then either set DHCLIENT_MODIFY_RESOLV_CONF=no
# in /etc/sysconfig/network/dhcp, or
# set MODIFY_RESOLV_CONF_DYNAMICALLY=no in
# /etc/sysconfig/network/config or (manually) use dhcpcd
# with -R. If you only want to keep your searchlist, set
# DHCLIENT_KEEP_SEARCHLIST=yes in /etc/sysconfig/network/dhcp
or
# (manually) use the -K option.
#
### END INFO
domain localdomain
nameserver 192.168.2.1
~>

What does the "hosts:" entry in
/etc/nsswitch.conf read?

cat /etc/nsswitch.conf
#
# /etc/nsswitch.conf
#
# An example Name Service Switch config file. This file should be
# sorted with the most-used services at the beginning.
#
# The entry '[NOTFOUND=return]' means that the search for an
# entry should stop if the search in the previous entry turned
# up nothing. Note that if the search failed due to some other reason
# (like no NIS server responding) then the search continues with the
# next entry.
#
# Legal entries are:
#
# compat Use compatibility setup
# nisplus Use NIS+ (NIS version 3)
# nis Use NIS (NIS version 2), also called YP
# dns Use DNS (Domain Name Service)
# files Use the local files
# [NOTFOUND=return] Stop searching if not found so far
#
# For more information, please read the nsswitch.conf.5 manual page.
#

# passwd: files nis
# shadow: files nis
# group: files nis

passwd: compat
group: compat

hosts: files dns
networks: files dns

services: files
protocols: files
rpc: files
ethers: files
netmasks: files
netgroup: files nis
publickey: files

bootparams: files
automount: files nis
aliases: files

~>

Regards, Ian

That's the infroamtion which you ask for. Does this give an indication?

Thanks for helping and looking into it!

NoKo
--
"Careful with that VAX, Eugene!"
.

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