To be able to subscribe to another farm's content, there has to be a trust relationship set up between the two farms. This gives the two server farms, the ability to communicate. This is accomplished through certificates that uniquely identify the farms.
In this recipe you will see how to set this up.
Because we are showing this with PowerShell, you must be a member of the
SharePoint_Shell_Access database role on the configuration database of both the publishing farm and consuming farm. You also must be a member of the
WSS_ADMIN_WPG local group on the chosen servers.
Finally, the two servers you will be using (one on the Publishing Farm and one on the Consuming Farm) must be selected ...