Problems setting up DNS, gateway und subnetmask!

[Henk Koster]

On Wed, 28 Dec 2005 02:07:02 +0200, Tamer Higazi wrote:

> Hi!
> I have received from my ISP an IP, DNS, Subnetmask and the DNS 
> Serverentries to add to my ubuntu linux machine

Whoa! This is where you are wrong already -- these data are for your 
ADSL router; your Ubuntu Linux machine is on the inside 10.0.0.0/24 LAN.

> My interfaces File /etc/network/interfaces: # This file describes the
> network interfaces available on your system # and how to activate them.
> For more information, see interfaces(5).
> 
> # The loopback network interface
> auto lo
> iface lo inet loopback
> address 127.0.0.1
> netmask 255.0.0.0
> 
> # This is a list of hotpluggable network interfaces. # They will be
> activated automatically by the hotplug subsystem. mapping hotplug
> script grep
> map eth0
> 
> # The primary network interface
> 
> 
> auto eth0
> 
> iface eth0 inet static
> address 81.10.53.22
> netmask 255.255.255.252
> gateway 10.0.0.138
> dns-search lan
> dns-nameservers 163.121.128.134 212.103.160.18

This is a mix of LAN and Internet... no wonder it doesn't work.
I recommend you change it to 

auto eth0
iface eth0 inet dhcp

The router is also the nameserver for the LAN, so make sure that
/etc/resolv.conf reads as follows:

search lan
nameserver 10.0.0.138

With these settings you have a route from your Linux machine to the LAN,
so next login with your browser to the router at http://10.0.0.138. You
must configure the router with the information given:

PPPoA interface: IP/netmask    81.10.53.22/32
                 Primary DNS   163.121.128.134
                 Secondary DNS 212.103.160.18

eth0 interface: 10.0.0.138/24

Routing: 10.0.0.0 to gateway 10.0.0.138 at interface eth0
         default  to gateway 81.10.53.22 at interface PPPoA
         ... plus localhost, etc.

DNS for the lan is 10.0.0.138

Chances are that most of this is already set in a configuration file
on a CD provided by your ISP -- you might even want to configure the
router automatically with this CD in Windows... 

> My File /etc/hosts:
> 
> 127.0.0.1 localhost.localdomain localhost ubuntu # The following lines
> are desirable for IPv6 capable hosts fe00::0 ip6-localnet ff00::0
> ip6-mcastprefix
> ff02::1 ip6-allnodes
> ff02::2 ip6-allrouters
> ff02::3 ip6-allhosts
> 
> If I enter the command route:
> 
> Kernel IP Routentabelle
> Ziel Router Genmask Flags Metric Ref Use Iface 81.10.53.20 *
> 255.255.255.252 U 0 0 0 eth0
> 
> If I run explicitly this command to add the gateway to my eth0
> interface:
> 
> 
> sudo route add default gateway 10.0.0.138 eth0
> 
> I receive this errormessage:
> SIOCADDRT: Das Netzwerk ist nicht erreichbar (Network unreachable)
> 
> 
> For any help solving my problem, thanks in advance
> 
> Tamer

-- 
H.A.J. Koster
"Behavioral axioms are right, but agents make mistakes..."
(attributed to L.J. Savage)