Elasticsearch available on internal and public ip

[DavidTurner]

I don't think this is possible, a node can only have one HTTP publish address so you must choose which one you want.

Rather than using sniffing, can you set up DNS and use a StaticConnectionPool?

Also note that you shouldn't expose Elasticsearch to the public internet.

@Bertram_van_de_Ven

Is it "only" adding the external ip(s) to the discovery.zen.ping.unicast.hosts ?

This setting is purely about nodes in the cluster discovering each other. It has no bearing on anything to do with HTTP.