The ultimate goal is to allow a remote data connection service to operate on port 443 on a the SQL server. The application accessing the connection is behind a firewall and it is because of the client's reluctance to open another port that I have been asked to try and get this working. The current environment is Windows 2003 R2 (SP2) and SQL Server 2005. IIS is not installed, but when I try and install the third party connection software (SequeLink) it won't as it reports something is still configured on/using port 443.

Netstat does not show anything listening on the port and I've tried editing the system32\drivers\etc\services file removing any reference to port 443 and also using sc delete to delete the HTTP and HTTPFilter (HTTP SSL in services console) services to see if this would help. Rebooting after each change.

What could still be using the port? Is what I'm trying even possible (I have my doubts but have to investigate every avenue)?

Any help/pointers would be greatly appreciated.