github wiki或sourceforge wiki上没有描述如何执行此操作，只是如何执行此操作
有一个文件
/etc/default/ddclient
# Configuration for ddclient scripts
# generated from debconf on Thu Jul 27 17:32:33 ACST 2017
#
# /etc/default/ddclient
# Set to "true" if ddclient should be run every time DHCP client ('dhclient'
# from package isc-dhcp-client) updates the systems IP address.
run_dhclient="false"
# Set to "true" if ddclient should be run every time a new ppp connection is
# established. This might be useful, if you are using dial-on-demand.
run_ipup="false"
# …