Kubuntu DNS settings

Seem like DNS settings are no longer stored in resolv.conf but this can still be extracted from the netwok Manager CLI.

nmcli dev show [device] e.g. nmcli dev show wlan0

This will return information including:

IP4.DNS[1]:
IP4.DOMAIN[1]:

Therefore a quick awk can return the value needed:

nmcli dev show wlan0 | grep IP4.DNS | awk -F: '{ print $2 }' | awk '{ print $1 }'

Bind Dynamic DNS Updates

I saw a request to update Bind via a command line rather than Webmin for the ease and speed of a command line; So I embarked on investigating this.

Firstly it seems that there is not a lot of dynamic update or command line update scripts available or the people just don't want to share ???

I stumbled across nsupdate, an application that is part of the Bind suite.
This is a command line tool to add dynamic updates to an DNS server.

for this to work you need to update the specific zone file with at least the following configuration:

zone "example.com" {
type master;
file "/etc/bind/example.com.hosts";
allow-update {192.168.0.0/24; };
journal "/var/lib/bind/example.com.hosts.jnl";
};
For dynamic DNS you need:
allow-update
journal

then to add an entry to the DNS server:
from within the 192.168 ip range :

user@pc:~$ nsupdate
> zone example.com
> update add guest1.example.com. 86400 A 192.168.0.10
> send
> quit

your syslog on your DNS server will log all updates

Can't ping FQDN in Ubuntu

I created a local DNS zone ending in .local and experienced weird DNS behaviour; dig worked 100%

It seems the avahi-daemon interferes with the normal resolving process. It’s DNS caching borks the normal functionality

The fix:

# shut it down
sudo /etc/init.d/avahi-daemon stop
# stop it starting at the next reboot by removing the startup links
sudo update-rc.d -f avahi-daemon remove
 Removing any system startup links for /etc/init.d/avahi-daemon ...
   /etc/rc1.d/K86avahi-daemon
   /etc/rc2.d/S50avahi-daemon
   /etc/rc3.d/S50avahi-daemon
   /etc/rc4.d/S50avahi-daemon
   /etc/rc5.d/S50avahi-daemon