We have three servers for our setup:

• An internal server with the Umbraco admin site, using SetServerRegistrar to force it as the Master
• Two external, load-balanced servers without the Umbraco admin site, using SetServerRegistrar to force them as Replica

My questions are:

• Is it acceptable to set umbracoApplicationUrl in the web.config for all of servers? Do non-master servers care about this value? If the non-master servers don't use it then I might as well use one web.config value (the internal URL) instead of needing config transforms to set the external server values to null. Note, if it matters, the external servers are not able to access the internal URL.
• The Scheduling & Master Election article says that umbracoApplicationUrl needs to point to itself, the internal load balancer, or the public address. If one of the tasks controlled by this URL is keepalive, wouldn't that URL have to point directly to the master so the master stays alive? If it pointed at the public address or load balancer that keep alive call would end up the external, non-master machines.

Thank you for your help