iPrint can use any port specified on Apache; however, iPrint defaults to two primary ports:
Port 443: All secure printing occurs through SSL over port 443.
Port 631: All non-secure printing occurs over port 631.
The iPrint Client also supports TLS. If your system is configured to use TLS, 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. This is because iPrint uses CUPS to render print jobs before sending a job to the Print Manager, printing from the server itself by using CUPS, or if iPrint is not available.