Cannot resolve hostname

debian dns raspberry-pi hostname raspbian

6,085

Your /etc/network/interfaces is confused. There are several methods of assigning an IP address to the interface; you've specified dhcp which means to ask the DHCP server for an address. But then you went ahead and specified an address anyway.

I think what you want is something like this

auto lo
iface lo inet loopback

allow-hotplug eth0         # omit this line if using ifplugd
iface eth0 inet static
    address 139.182.112.9
    netmask a.b.c.d
    gateway 139.182.e.f

allow-hotplug wlan0

iface wlan0 inet manual
    wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf

iface default inet dhcp

You hopefully know the right netmask and gateway. If not, you'll need to get them from your network administrator. They should have been provided along with the IP address.

6,085

Carlos Perez

Updated on September 18, 2022

Comments

Carlos Perez over 1 year
I'm using a Debian on a RaspberryPi and the problem that I'm having is that I can't connect to the Internet.

Every time I try I see a message that says "cannot resolve hostname". From the terminal, I tried:
```
$ ping www.google.com 
unknown host google.com

$ ping 8.8.8.8
network is unreachable
```
output of 'ip addr list'
```
1: <LOOPBACK, UP, LOWER_UP> mt 65536 qdisc noqueue state UNKNOWN
   link/loopback 00:00:00:00:00:00 vrd 00:00:00:00:00:00:
   inet 127.0.0.1/8 scope host lo
      valid_lft forever preferred_lft forever

2: eth0: <BOADCAST, MULTICAST, UP, LOWER_UP> mtu 1500 dis pfifo_fast state UP qlen 100
   link/ether b8:27:eb:18:b9:17 brd ff:ff:ff:ff:ff:ff
```
This appears after doing the ifdown eth0 and ifup eth0 as drobert suggest
```
  innet 1393.182.112.9116 brd 139.182.255.255 scope global eth0
    valid_lft forevere preferred_lft forever
```
ip route ls
```
139.182.0.0/16 dev eth0 proto kernel scope link src 139.182.112.9
```
etc/network/interface
```
auto lo

iface lo inet loopback
iface eth0 inet dhcp

address 139.182.112.9

allow-hotplug wlan0
iface wlan0 inet manual
wpa-roam /etc/wpa_supplicant/wpa_supplicant.cong
iface default inet dhcp
```
ifconfig
```
bcast: 139.182.255.255
Mask: 255.255.0.0
```
I try the up route list command nothing happed
- Admin almost 10 years
  
  please post the contents of the following commands: ip addr list and ip route list. Your problem seems to be the lack of a default route to your gateway.
- Carlos Perez almost 10 years
  
  @nwildner I update my question
- Admin almost 10 years
  
  Well, it seems that you don´t even have an ip address. Try dhclient eth0 to aquire an address from your lan(if there is a dhcp server somewhere). Cheers :)
- Carlos Perez almost 10 years
  
  @nwildner nothing happend with the dhclient eth0 command :/
- Gilles 'SO- stop being evil' almost 10 years
  
  Your Pi isn't connected to any network. What kind of network connection does it have? Is there a cable plugged into eth0 and if so what's at the other end?
- Admin almost 10 years
  
  Hi Carlos. Does dhclient even return error or no screen response? It seems that you have connectivity(LOWER_UP on ip addr list) but you don´t have a L3 configuration(addressing/routing). Other computers connected to this network aquire ip address automatically?
- Carlos Perez almost 10 years
  
  @Gilles yes it is connected using a cable, and I assign the ip address on /et/network/interface/ and still having the same problem
- derobert almost 10 years
  
  @CarlosPerez Your ip addr ls output doesn't show an IP address. So for some reason the address you assigned in /etc/network/interfaces didn't take. I suggest ifdown eth0 (ignore any errors) and then seeing if you get an error from ifup eth0.
- Carlos Perez almost 10 years
  
  @derobert I try with the ifdown eth0 and ifup eth0 and im still having the same problem
- derobert almost 10 years
  
  @CarlosPerez did either produce an error message? Also, does ip addr ls show the IP address now? Does ip route ls show your default gateway? If not, please edit your question to include the /etc/network/interfaces (if you want to obscure the IP addresses, feel free to do so).
- Carlos Perez almost 10 years
  
  @derobert yes now the ip show after running the command ip addr ls I update my question
- derobert almost 10 years
  
  @CarlosPerez I'm going to assume the weird 4-digit octets in the IP address are just a mistake in editing the question. It appears you don't have a default gateway; did you specify one (with the gateway clause) in your /etc/network/interfaces? Also, make sure you have allow-hotplug eth0 or auto eth0 in there somewhere (otherwise, it won't be started on boot).
- Carlos Perez almost 10 years
  
  @derobert thanks for helping me, I update my question again, so you can see the etc/network/interface and the ifconfig. sorry but im reall y new at this :/
- derobert almost 10 years
  
  @CarlosPerez that is a very confused /etc/network/interfaces. Let me post an example as an answer, because I think that'll get it working for you. Keep in mind you must do an ifdown/ifup pair each time to make the changes take effect.
Carlos Perez almost 10 years

wooow you are a genius man, thank you so much :))
Ludwig Schulze almost 10 years

wlan with hotplug?
derobert almost 10 years

@Braiam allow-hotplug should bring it up when udev gets the device. I don't think OP is running Network Manager. Also not sure if OP is even using the wlan.