$ sudo apt-get remove libdns100 

Uninstall libdns100 including dependent package

If you would like to remove libdns100 and it's dependent packages which are no longer needed from Ubuntu,

$ sudo apt-get remove --auto-remove libdns100 

Use Purging libdns100

If you use with purge options to libdns100 package all the configuration and dependent packages will be removed.

$ sudo apt-get purge libdns100 

If you use purge options along with auto remove, will be removed everything regarding the package, It's really useful when you want to reinstall again.

$ sudo apt-get purge --auto-remove libdns100 

See Also,