Squid conf

squid.conf

http_port 3128

refresh_pattern -i .rpm$ 129600 100% 129600 refresh-ims override-expire
refresh_pattern -i .iso$ 129600 100% 129600 refresh-ims override-expire
refresh_pattern -i .deb$ 129600 100% 129600 refresh-ims override-expire
refresh_pattern -i .whl$ 129600 100% 129600 refresh-ims override-expire
refresh_pattern ^ftp:           1440    20%     10080
refresh_pattern ^gopher:        1440    0%      1440
refresh_pattern -i (/cgi-bin/|\?) 0     0%      0
refresh_pattern .               0       20%     4320

acl localnet src 10.0.0.0/8     # RFC 1918 possible internal network
acl localnet src 172.16.0.0/12  # RFC 1918 possible internal network
acl localnet src 192.168.0.0/16 # RFC 1918 possible internal network
acl localnet src fc00::/7       # RFC 4193 local private network range
acl localnet src fe80::/10      # RFC 4291 link-local (directly plugged) machines
acl all      src 0.0.0.0/0.0.0.0

acl SSL_ports port 443          # https

acl Safe_ports port 80          # http
acl Safe_ports port 21          # ftp
acl Safe_ports port 443         # https
acl Safe_ports port 70          # gopher
acl Safe_ports port 210         # wais
acl Safe_ports port 1025-65535  # unregistered ports
acl Safe_ports port 280         # http-mgmt
acl Safe_ports port 488         # gss-http
acl Safe_ports port 591         # filemaker
acl Safe_ports port 777         # multiling http

acl CONNECT method CONNECT

http_access allow manager localhost
http_access allow all
http_access deny manager
http_access deny !Safe_ports
http_access deny CONNECT !SSL_ports
http_access allow localhost

Install with sudo apt-get install squid

Run with sudo systemctl enable --now squid

If using nebula, open port 3128/tcp