When the destination host in the URL is not a fully qualified host name, the default domain and subdomain are used to arrive at the fully qualified name.
Assume that the entry in the Default Domains field of the administration console is:
red.sesta.com |
You need to have the corresponding entry in the Proxies for Domains and Subdomains list.
In the example above, sesta.com is the default domain and the default subdomain is red.
If the requested URL is host1, this entry is resolved to host1.red.sesta.com using the default domain and subdomain. The Proxies for Domains and Subdomains list is then checked for host1.red.sesta.com.