information on alternate address should include note about port forwarding

The information on alternate address feature (https://docs.couchbase.com/server/current/learn/clusters-and-availability/connectivity.html#alternate-addresses) should mention port forwarding, which needs to be enabled from target alternate ip:alternate port to target internal ip:<usual_service_port> for alternate address to work (when using different port numbers).

This Couchbase blog has good information on this – https://blog.couchbase.com/alternate-address-por-support-for-couchbase-n1ql-clusters/    In the section on "Alternate address setup steps", in step 3, it has an example – "For port forwarding on a virtual machine, we can use the following command for the Query service running on port 8093".