22.2.7          What is a Firewall and TCP Port?

If your connection to the WebAccess DRAW or VIEW fails, but connection to the Configuration Manager worked, then a firewall is the most likely reason.

A Firewall restricts the flow of data onto a network; it is a method of network security. Many corporations use firewalls. If your connection is through a firewall, you will need to have your network administrator open two TCP ports for you to use the DRAW or VIEW features in WebAccess. You should be able to use the Configuration Manager without having TCP ports opened for you. This only applies if you are connecting through the firewall. If all your WebAccess Clients and SCADA nodes are inside the firewall, you can ignore this. The TCP ports are set on the SCADA node. You can see the TCP Ports listed in the Project Manager described in Section 1. Note that 0 means the default ports numbers are used (80 for HTTP Port, 4592 for Primary and 14592 for Secondary).