安装stunnel及squid等
yum install stunnel squid openssl openssl-devel -y

配置并启用squid服务
systemctl enable squid
systemctl start squid

创建stunnel配置文件
cp /usr/share/doc/stunnel-4.56/stunnel.conf-sample /etc/stunnel/stunnel.conf
vi /etc/stunnel/stunnel.conf
在Service definitions处加入
[squid]
accept = 8888
connect = 127.0.0.1:3128
cert = /etc/stunnel/stunnel.pem

创建stunnel密钥
openssl genrsa -out key.pem 2048
openssl req -new -x509 -key key.pem -out cert.pem -days 3650
cat key.pem cert.pem >> /etc/stunnel/stunnel.pem

创建stunnel运行目录
mkdir /var/run/stunnel
chown nobody:nobody /var/run/stunnel

创建stunnel启动脚本
vi /etc/systemd/system/stunnel.service
; systemd script for stunnel. Please put this file in
; /etc/systemd/system/stunnel.service or /usr/lib/systemd/system/stunnel.service
[Unit]
Description=SSL tunnel for network daemons
After=syslog.target
[Service]
ExecStart=/usr/bin/stunnel /etc/stunnel/stunnel.conf
ExecStop=kill -9 $(pgrep stunnel)
ExecStatus=pgrep stunnel
Type=forking
[Install]
WantedBy=multi-user.target

配置并启用stunnel服务
systemctl enable stunnel
systemctl start stunnel

下载stunnel客户端
https://www.stunnel.org/downloads.html

修改客户端stunnel.conf配置，在Service definitions处加入
[squid]
client = yes
accept = 127.0.0.1:8080
connect = X.X.X.X:8888
cert = stunnel.pem