Apache Reference: mod_proxy, AllowCONNECT

AllowCONNECT

Ports to Which the HTTP CONNECT Method Is Allowed to Connect
Syntax: AllowCONNECT port [port ...]
Example: AllowCONNECT 443 563 8443 8563
Since: Apache 1.3

This directive configures the ports to which the HTTP CONNECT proxy method is allowed to connect. By default, only the HTTPS (443) and SNEWS (563) ports are allowed.