Supporter Multisite

I am having two issues.

1) We recently moved to a VPS using Plesk control panel. It has one static IP address that is shared among several sites we maintain or are developing one of which is a Supporter powered multisite. In Plesk there is an option to define the "default domain" for the shared IP address (i.e., primarysite.com). When navigating to the dashboards for member sites (i.e., site2.example.com/wp-admin/) I get redirected to something like this...

http://primarysite.com/wp-login.php?redirect_to=http%3A%2F%2Fsite2.example.com%2Fwp-admin%2F&reauth=1

When I set the default site to be example.com, then example.com becomes unavailable. On shared hosting this did not happen. The main reason we moved to the VPS was to get the static IP for domain masking. Does a Supporter powered site network required a dedicated IP or just a static IP? And any thoughts on the IP settings in Plesk?

2) How can I set it up so that when an admin for one of our member sites logs in at the landing page for our network, they get redirected to the dashboard for their member site. It does this on edublogs, but I'm not sure how.

Thanks

    Aaron

    Does a Supporter powered site network required a dedicated IP or just a static IP?

    Supporter has nothing to do with IPs.

    2) How can I set it up so that when an admin for one of our member sites logs in at the landing page for our network, they get redirected to the dashboard for their member site. It does this on edublogs, but I'm not sure how.

    That should be default behavior, unless they are a member of the main blog as well. I think it goes by their primary site setting in the dashboard.