I've worked with several implementations where there have been issues with configuring a PeopleSoft gateway on a firewall in the DMZ (typically for candidate gateway implementations). The webserver in the DMZ will have the gateway running, and when we attempt to load the connectors then we receive the message 'External system contact exception'. I know that there is some configuration required within the firewall; in the most recent instance there was a firewall rule to allow the webserver to access the app server within the firewall.
My question is - what is the connection that is occurring when loading the gateway connectors? Is there a particular firewall setting I should be looking for that will allow this operation to occur?
I wanted to follow up on this in case anyone else is seeing the same issue. The solution was to ensure that the external web server had access to the internal web server as well as the internal application server. Once this firewall rule was entered, then the gateway connectors loaded successfully.