I basically followed the steps in Spence Harbars Guide http://www.harbar.net/articles/sp2010mt1.aspx do create a multi-tenancy farm with host-header site-collections.
For some reason I cannot supply a template when creating the tenant-sites, I always get "There are no addresses available for this application." So I create the new site without a template and then call
set-spsite -template sts#0. This gives me the same message, but looking with SharePoint Manager in the site, I have STS as the associated web-template.
However ... when I open up IE and want to browse to the site (http:/portal.corp-a.local) I get a 404 ...
OK, now I'm lost/stuck. What went wrong? ULS doesn't include any error. Any hints?