yum 出现epel错误，如何处理！
yum的时候出现一下错误： Error: Cannot retrieve metalink for repository: epel. Please verify its path and try again简单粗暴的解决方案是：yum --disablerepo=epel -y update ca-certificates
Letsencrypt免费CA证书过期后续期
用Letsencrypt建立了IKE v2的VPN，证书过期后如何处理！！sudo ~/.local/share/letsencrypt/bin/letsencrypt renewcd /etc/letsencrypt/live/域名/ cp -f chain.pem /root/ca.cert.pem cp -f cert.pem /root/server.cert.pem cp -f priv