You can find all ports that are allowed in the configuration file like this:
... acl Safe_ports port 80 ... </code> Consider adding Safe_ports ACL rule for any port that your clients need. ---- You can add a port range instead of writing a rule for every port like this: <file bash /etc/squid/squid.conf> ... acl Safe_ports port 6000-7000 ...
sudo systemctl restart squid