Hello David,
GSS doesn't announce anything. It responds to dns queries that it receives based on his configuration. In any case, GSS must be configued as an authoritative dns server for the relevant domains / subdomains (should be those listed in the GSS domain lists) in the uper level dns server. Without this, no requests will ever reach your GSS...
So for instance:
abc.com --> authoritative serve: the abc company name server
www.abc.com --> authoritative server: the GSS
DNS requests only resolve hostnames. So "cisco.com/tool" will only trigger a resolution for "cisco.com".
I hope it helps.
Olivier