Squid Proxy

sudo apt-get install squid

vi /etc/squid/squid.conf

#Comment out as below:
#http_access deny all

#Add the below:
acl remote src all
http_access allow remote

Restart squid:

systemctl restart squid

Configure firewall to allow port 3128 from desired IPs only, otherwise this config will allow anyone from accessing it or nobody depending on firewall config.