Merge #2870

2870: Add comment about IPv4/IPv6 connectivity r=coot a=weebl2000

Since #2773 was rejected.

Co-authored-by: Wessel Nieboer <wessel.nieboer@onior.com>

doc/stake-pool-operations/core_relay.md

@@ -44,3 +44,7 @@ Make your __relay node__ `talk` to your __block-producing__ node and __other rel
         }
       ]
     }
+
+**Note**: If you want to connect to IPv4 and IPv6 relays, you must either not
+specify host addresses when starting `cardano-node` or make sure to specify
+both an IPv4 and IPv6 host address.

doc/stake-pool-operations/getConfigFiles_AND_Connect.md

@@ -44,6 +44,7 @@ Get the complete list of available options with `cardano-node run --help`
   	                                specified slot
     -h,--help                       Show this help text
 
+**Note**: If you do not specify `--host-addr` nor `--host-ipv6-addr`, node will use the default IPv4 and IPv6 addresses (depending which addresses are available).  If one specifies one of them only that address will be used, in particular if you only provide an IPv4 address, the node will not connect over IPv6.
 To start a passive node:
 
      cardano-node run \