I have a Laptop with Debian Jessie installed. At my home network, I could connect successfully to the internet (
ping google.de successful). At the external network, I can't ping google.de (result: unknown host google.de), although I can ping 188.8.131.52 and 184.108.40.206 (those are the Google public DNS servers)
/etc/resolv.conf was configured to use a private DNS resolver(nameserver 255.0.0.0) at home, therefore it doesn't work at the external network. Changing that to nameserver 220.127.116.11 and 18.104.22.168 as suggested in 1 doesn't help, it is overwritten after the
dhclient is run.
chmod -w /etc/resolv.conf (it has now only read permissions) also doesn't help. It is still overwritten when running
ifdown and those legacy tools to connect.
source /etc/network/interfaces.d/* allow-hotplug wlan0 auto wlan0 iface wlan0 inet dhcp wpa-ssid <...> wpa-psk <...> </code>
Now my question:
You need to make sure DHCP (if in use) is configured correctly, and your local DHCP server (usually your cable / adsl modem) is handing out the right details.
How do I do that? I can't use this suggestion, because obviously I have no internet connection.