bundle install や gem update が実行できない問題に遭遇した

PS > bundle install
Fetching source index from https://rubygems.org/
Retrying fetcher due to error (2/4): Bundler::HTTPError Could not fetch specs from https://rubygems.org/
Retrying fetcher due to error (3/4): Bundler::HTTPError Could not fetch specs from https://rubygems.org/
Retrying fetcher due to error (4/4): Bundler::HTTPError Could not fetch specs from https://rubygems.org/
Could not fetch specs from https://rubygems.org/

PS > gem update bundler
ERROR:  While executing gem ... (Gem::RemoteFetcher::UnknownHostError)
    no such name (https://rubygems.org/specs.4.8.gz)

原因？

ネットで調べると rubygems.org に対して IPv6でアクセスできないとか

解決方法

hostsにIPv4アドレスを記載する

PS > nslookup.exe "rubygems.org"
# 出力された ipv4アドレス（4件くらい）をメモ

hosts を編集

Windows\System32\drivers\etc\hosts

# XXX.XXX.XXX.XXX にメモしたipv4アドレスを記載
XXX.XXX.XXX.XXX rubygems.org
XXX.XXX.XXX.XXX rubygems.org
XXX.XXX.XXX.XXX rubygems.org
XXX.XXX.XXX.XXX rubygems.org

上記の対応でgemやbundleコマンドの実行ができた