I have been following this guide on setting up VPN on my pi.
Part of the steps are to set up and configure a dynamic dns service.
Like many people I use Open DNS instead of my internet provider’s DNS.
=============================================================================== ddclient is a Perl client used to update dynamic DNS entries for accounts on many dynamic DNS services.
=============================================================================== Dynamic DNS services currently supported include: Dyn - See details on obtaining a free account. Name Cheap - See details Con Cont - See for details Dns Park - See details Dsl Reports - See details Sitelutions - See details Loopia - See details Noip - See for details Freedns - See for details Change IP - See for details dtdns - See for details nsupdate - See nsupdate(1) and ddns-confgen(8) for details Cloud Flare - See https:// for details Google - See for details Duckdns - See https://duckdns.org/ for details Freemyip - See https://for details - See https://woima.fi/ for details DDclient now supports many of cable/dsl broadband routers.
USING DDCLIENT WITH dhcpcd-1.3.17 If you are using dhcpcd-1.3.17 or thereabouts, you can easily update your Dyn DNS entry automatically every time your lease is obtained or renewed by creating an executable file named: /etc/dhcpc/ie.: cp sample-etc_dhcpc_dhcpcd-eth0/etc/dhcpc/In my case, it is named dhcpcd-eth0and contains the lines: Other DHCP clients may have another method of calling out to programs for updating DNS entries.
Alternatively, you may just configure ddclient to operate as a daemon and monitor your ethernet interface.