SELinux is based on the least level of access required for a service to run. Services can be run in a variety of ways; therefore, you must tell SELinux how you are running services. The following Boolean allows you to tell SELinux how you are running Squid:
squid_connect_any
When enabled, this Boolean permits squid to initiate a connection to a remote host on any port.
squid_use_tproxy
When enabled, this Boolean allows Squid to run as a transparent proxy.