Slackみたいな無料のオープンショースチャットサーバ

https://rocket.chat/docs/installation/manual-installation/centos/

<VirtualHost _default_:443>

ServerName chat01.fl8.jp
 SSLEngine on
 SSLProtocol all -SSLv2 -SSLv3
 SSLCipherSuite ALL:!ADH:!EXPORT:!SSLv2:RC4+RSA:+HIGH:+MEDIUM:+LOW
 SSLCertificateFile /etc/letsencrypt/live/chat01.fl8.jp/cert.pem
 SSLCertificateKeyFile /etc/letsencrypt/live/chat01.fl8.jp/privkey.pem
 SSLCACertificateFile /etc/letsencrypt/live/chat01.fl8.jp/chain.pem
# Rochet.Chat
SSLOptions +StrictRequire
ProxyPreserveHost On
ProxyPass /websocket ws://localhost:3000/websocket
ProxyPassMatch ^/sockjs/(.*)/websocket ws://localhost:3000/sockjs/$1/websocket
ProxyRequests Off
ProxyPass / http://127.0.0.1:3000/
ProxyPassReverse / http://127.0.0.1:3000/

</VirtualHost>