初めてのドメイン名をラズパイに割り当てて、外部ネットワークから接続できるようにしてみた ref: https://qiita.com/moppymopperson/items/e97882b28ef543cd9a5e

file0.txt

sudo apt install ddclient

file1.txt

use=web, web=checkip.dyndns.com/, web-skip='IP Address'
ssl=yes
protocol=namecheap
server=dynamicdns.park-your-domain.com
login=nihongoheta.club
password=<機密情報>
www

file2.txt

● ddclient.service - LSB: Update dynamic domain name service entries
   Loaded: loaded (/etc/init.d/ddclient; bad; vendor preset: enabled)
   Active: active (exited) since Sun 2018-02-11 08:09:56 EST; 13h ago
     Docs: man:systemd-sysv-generator(8)

Feb 11 08:09:56 bitbuster systemd[1]: Starting LSB: Update dynamic domain name service entries...
Feb 11 08:09:56 bitbuster systemd[1]: Started LSB: Update dynamic domain name service entries.
Feb 11 08:25:45 bitbuster systemd[1]: Started LSB: Update dynamic domain name service entries.
Feb 11 20:01:11 bitbuster systemd[1]: Started LSB: Update dynamic domain name service entries.
Feb 11 20:10:13 bitbuster systemd[1]: Started LSB: Update dynamic domain name service entries.
Feb 11 20:14:45 bitbuster systemd[1]: Started LSB: Update dynamic domain name service entries.
Feb 11 20:53:09 bitbuster systemd[1]: Started LSB: Update dynamic domain name service entries.