How to resolve names

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.

Addressrange is 192.168.2.101 - ...200
Mask is 255.255.255.0
So nothing unusual.

What am I missing here?

Thanks,

NoKo

--
"Careful with that VAX, Eugene!"

"Norbert Kolvenbach" <noko4711@t-online.de> wrote in message
news:etjqtq$h2h$01$1@news.t-online.com...
> 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.
>
> Addressrange is 192.168.2.101 - ...200
> Mask is 255.255.255.0
> So nothing unusual.
>
> What am I missing here?
>
> Thanks,
>
> NoKo

Hi,

Two ways to get what you want:

1.-------
/etc/hosts
It is self-explanatory. All the PC's will need entries for the other
computers in their /etc/hosts file. Very simple and practical when you just
have a few PC's.

2. -------
named (DNS daemon)
More work involved and probably not "practical" when you just a have PC's,
but you run it as just a caching DNS server and also have your own 192.168
zone. Then you just point all your PC's to the PC running named for DNS
resolution and not have to maintain host tables on all the PC's. (Point it
at the DNS-serving PC in /etc/resolv.conf) Again, its not really
"practical" (unless, of course, you just want to learn how it works) when
you just have a few PC's, but it would and even be more "seamless" than
using /etc/hosts.

Norbert Kolvenbach <noko4711@t-online.de> wrote:
> So I can ping and try to ssh/telnet the 2 other machines from my PC via
> ip-address (no supprise).

Does ping and telnet to their dynamically allocated IP addresses work?

--
Mark Hobley
393 Quinton Road West
QUINTON
Birmingham
B32 1QE

Telephone: (0121) 247 1596
International: 0044 121 247 1596

Email: markhobley at hotpop dot donottypethisbit com

http://markhobley.yi.org/

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.

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?

What output/errors are issued when you:

ping <name>

dig <name>

host <name>

getent hosts <name>

?

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

Regards, Ian

Mark Hobley wrote:

> Norbert Kolvenbach <noko4711@t-online.de> wrote:
>> So I can ping and try to ssh/telnet the 2 other machines from my PC via
>> ip-address (no supprise).
>
> Does ping and telnet to their dynamically allocated IP addresses work?
>

Yes, ping with ip address works.

NoKo

--
"Careful with that VAX, Eugene!"

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.
>
> 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!"

On Mon, 19 Mar 2007, Norbert Kolvenbach wrote:

> 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.
>>
>> 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
>

What do your DNS server config files look like (the ones in that are
probably in /var/named and /etc/named.conf or whatever files you are
using) Your DNS server is 192.168.2.1 right?

--
Sir Jackery

Sir Jackery wrote:

> On Mon, 19 Mar 2007, Norbert Kolvenbach wrote:
>
>> 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.
>>>
>>> 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
>>
>
> What do your DNS server config files look like (the ones in that are
> probably in /var/named and /etc/named.conf or whatever files you are
> using) Your DNS server is 192.168.2.1 right?
>
Yes, and it is a plug and play box with a web interface and firmware. I
cannot access configuration files.

Noko
--
"Careful with that VAX, Eugene!"

On Mon, 19 Mar 2007 17:54:54 +0100, Norbert Kolvenbach wrote:

> Ian Northeast wrote:

>> 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

Now that's odd. I assume you issued the dig command with the unqualified
name, i.e. not followed by ".localdomain" which as per your resolv.conf is
your domain name. That shouldn't have worked. That response is for a fully
qualified name of just <name> - see that "." at the end. This isn't right.
I think your router's DNS server is misbehaving.

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

Is that right? Three responses, one with the correct address and two
errors?

Try issuing "ping <name>." complete with the trailing ".".

Are any firmware updates available for your router?

Regards, Ian

Ian Northeast wrote:

> On Mon, 19 Mar 2007 17:54:54 +0100, Norbert Kolvenbach wrote:
>
>> Ian Northeast wrote:
>
>>> 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
>
> Now that's odd. I assume you issued the dig command with the unqualified
> name, i.e. not followed by ".localdomain" which as per your resolv.conf is
> your domain name. That shouldn't have worked. That response is for a fully
> qualified name of just <name> - see that "." at the end. This isn't right.
> I think your router's DNS server is misbehaving.
>

Yes I issued "dig name" and not "dig name.localdomain".
The latter does not work as you laid out.


>>> host <name>
>> ~> host <name>
>> <name> has address 192.168.2.101
>> Host <name> not found: 3(NXDOMAIN)
>> Host <name> not found: 3(NXDOMAIN)
>
> Is that right? Three responses, one with the correct address and two
> errors?
>

Yes, 3 responses.

> Try issuing "ping <name>." complete with the trailing ".".
>
> Are any firmware updates available for your router?
>

Interestingly "ping <name>." works!

Firmware updates are notr available yet. It is a brand new hardware.


Regards,

NoKo

--
"Careful with that VAX, Eugene!"