About creating additional portals

When you add portals, you have these options:

To use the same host name and port number combination, you must specify a unique portal site name for each portal you add. This is the recommended option. For example, for the existing website http://www.acme.com, you could add testportal as the portal site. The URL would be displayed as http://www.acme.com/testportal.
Use a different port number for each portal you add. The port number is specified in the Advanced Options section of the New Portal form. This is not recommended for production sites because the standard numbers are 80 for http and 443 for https, and they do not have to be entered by a user. If non-standard ports are specified, users would need to know the non-standard numbers in order to enter the URL. Also, you would need to open the non-standard ports through any firewalls that are in place and make sure there are no port conflicts with other applications on the farm servers.
In the Farm Manager, add a separate host name for each portal you plan to create.

For IIS bindings, IPF uses the host name/port and does not use specific IP address bindings.

When running IPF with IIS 7.5, https does not allow bindings to use the host name. So in this case, when https is used, only the port is used to identify the site binding. When adding a portal with the https protocol, make sure the port is not already in use, or if it is in use, make sure the host name for this portal is using the same digital certificate as the host name for any other portals that are already configured for https on this port.

For example, if the first portal URL created is https://acme.com, this shows other possible portal URLs and whether they are valid:

https://acme.com/test is valid
https://foo.com is invalid
https://test.acme.com is invalid

If the certificate is a wildcard certificate for *.acme.com, this shows sample portal URLs and whether they are valid:

https://kfkdkdkf42.acme.com attached to *.acme.com is valid
https://acme.com attached to *.acme.com is invalid
https://subtest.test.acme.com attached to *.acme.com is invalid
https://foo.acme2.com is not possible, since you cannot use a digital certificate of *.acme2.com in IIS when there is already a certificate for *.acme.com in use.

When running IPF with IIS 8.0, https does allow bindings to use the host name. So in this case, you can use *.acme.com and *.acme2.com at the same time. This shows sample portal URLs and whether they are valid:

https://kfkdkdkf42.acme.com attached to *.acme.com is valid
https://foo.acme2.com attached to *.acme2.com is valid
https://acme.com attached to *.acme.com is invalid
https://subtest.test.acme.com attached to *.acme.com is invalid