iPrint can use any port specified on Apache; however, iPrint defaults to two primary ports:
Port 443: All secure printing occurs over port 443 using SSL.
Port 631: All non-secure printing occurs over port 631.
The iPrint Client also supports TLS. If your system is configured to use TLS including the client, all secure and non-secure printing occurs over port 631.
During the OES install of the iPrint software, the CUPS back-end components are disabled on the server to avoid port 631 conflicts. Because iPrint uses CUPS to render print jobs before sending the print job to the Print Manager, printing from the server itself using CUPS or iPrint is not available.