IPv4
例
192.0.2.1
https://note.mu/ruiu/n/n9a8c4bfbee5a
https://www.geekpage.jp/blog/?id=2019-10-7-1
https://gigazine.net/news/20210426-mystery-pentagon-ip-addresses/
AWSが2023/2からIPv4に対し0.005$/h課金する
https://aws.amazon.com/jp/blogs/aws/new-aws-public-ipv4-address-charge-public-ip-insights/
/sorah-public/AWS Public IPv4 Address Charge