I have removed all member servers from a single domain A. I have demoted the single Windows Server 2008 R2 domain controller (old dc). Windows firewall is disabled and remote desktop (termserv) services is running. The issue is that old dc will not respond to requests on the external IP address. netstat shows termserv is listening on 0.0.0.0:3389 (all interfaces) and Windows firewall is disabled across all groups. When I telnet to old dc from an external machine there is no response. I know RDS is listening and responding as I am able connect using localhost/127.0.0.1 from old dc itself.
Any help is appreciated.