You can set this up from either the ASAP UI (which updates the relevant execution server’s nimi config file) or you can update the nimi config file directly.
From within the ASAP UI go to the Administration tab:
Select Agent Management
Under the Agent Title, select the execution server that is inside the firewall
Select the edit icon at the top right (pencil)
At the bottom tick the execution server(s) that is outside the firewall.
This will set up a link between the two execution servers with the inside execution server driving the connection
regards