Thank you for the reply.
When using FileMaker's Network Sharing, Port 5003 will need to be open on both the server and the client, incoming and outgoing.
For more information on how to properly configure Microsoft's Windows Firewall, consult the experts at Microsoft:
If the files are not showing after adding a rule, then test to see if port 5003 returns as open from the FileMaker Pro client to the FileMaker Server host.
On the client machine, install Telnet. Afterwards, open the command prompt (Start > CMD ) and use the following syntax to check the port:
Telnet <FileMaker Server I.P. Address> 5003
If the connection does not return a "blinking cursor" or times out, then the port is still blocked.
Please let me know if any of the above requires further clarification.