How do I install the update client or the DNS client on my Ubuntu server?

You can check out the instrucitons at https://www.dynu.com/DynamicDNS/IPUpdateClient/Linux.

Thanks, although I need instructions on how to edit the ddclient.conf since my broadband router is a Virgin Media Hub3.0 and there is no username, the only password is being used.

use=cisco, fw=192.168.1.1:80, fw-login=ADMIN, fw-password=ADMIN # Get ip from router.
is the 192.168.1.1:80 the ip address of my broadband router?

What do I put in the use= and fw-login= ???
Again my broadband router only has a password in order for you to access it.

Hi, first and foremost the link you gave me is very generic in nature.
I tried to use this command and it only returned a message of
# dpkg -i https://www.dynu.com/support/downloadfile/31
dpkg: error processing archive https://www.dynu.com/support/downloadfile/31 (--install):
cannot access archive: No such file or directory
Errors were encountered while processing:
https://www.dynu.com/support/downloadfile/31

So next step is I used the ddclient and I was able to install it on my Ubuntu Server 16.04.2 LTS.

Now I am having trouble in how to fill in the /etc/ddclient.conf

daemon=60
syslog=yes
mail=root
mail-failure=root
root.
pid=/var/run/ddclient.pic
use=cisco, fw=192.168.0.1:80, fw-login=WHATDOIPUTHERE?, fw-password=ISTHISMYROUTERPASSWORD?
server=api.dynu.com
protocol=dyndns2
login=MYLOGINTODYNU.COM?
password=MYPASSWORDATDYNU.COM?
ssword.
server321.dynu.net #SERVER I have configured in dyndns service.

Please help to clarify

this is the result:
# /usr/sbin/ddclient -daemon 300 -syslog
WARNING: skipping host: server321.dynu.net: 'login=' is an invalid login.
WARNING: skipping host: ssword.: 'login=' is an invalid login.
WARNING: skipping host: root.: 'login=' is an invalid login.

You may be better off using IP detection from server instead of the router:

use=web, web=checkip.dynu.com/, web-skip='IP Address' # Get ip from server.

instead of use=cisco, fw=192.168.1.1:80, fw-login=ADMIN, fw-password=ADMIN # Get ip from router..

DDClient config files can be found here.