Port No and Secure Communication between R/3 and Portal

Hi All,

We have a requirement where client says ,there needs to be a SSL tunnel established between SAP R/3 and Portal to access R/3 through portal.We would be using webgui with ITS for this.

Do we have to use SSL for that or SNC?I heard SNC is a mechanism which have to be used here since it uses DIAG protocol to connect but not Http.Is it true?Kindly give some more ideas on this.

Other thing is to do this they need to open a port between for using Firewall.Can you guide which SAP port has to be open for this connection?

Thanks In Advance

Regards

Rani A