To determine if a port such as 80 or 5432 has been opened on a server, do the following on the machine trying to connect to the server.
Instructions
1. Download the PortQry utility (to download, for information)
...
c:\PortQryV2\portqry -n <server-name or ip> -p both -e <port>
Ex:
c:\PortQryV2\portqry -n 192.168.1.100 -p both -e 5432
If the port is open, it should be listed with status of LISTENING. For example:
...