In a standard web session, Pressero will use port 443. It is also possible to use port 80, though that is not encouraged. That would apply to a user who logs into a B2C or B2B site and initiates an order through a web session. Using SAML also will happen over ports 443, or 80. Pressero will communicate with local LDAP over port 389. There is no synchronization of users on LDAP and SAML, only the ability to check passwords on login.
Note that the difference between port 443 (secure) or 80 (insecure) depends on if the site is set to use a secure certificate. We encourage all sites to be secure, the capability to make any of your sites secure is included with your account, and that functionality is available on the Settings > Domains
window for your site.