diff --git a/doc/guide/bind10-guide.xml b/doc/guide/bind10-guide.xml index e2b39619f7..c868a55212 100644 --- a/doc/guide/bind10-guide.xml +++ b/doc/guide/bind10-guide.xml @@ -1352,6 +1352,24 @@ This may be a temporary setting until then. and port number. By default, b10-auth listens on port 53 on the IPv6 (::) and IPv4 (0.0.0.0) wildcard addresses. + + + The default configuration is not appropriate for a multi-homed host. + In case you have multiple public IP addresses, it is possible the + query UDP packet comes through one interface and the answer goes out + through another. This will probably be dropped by the client, as it + has a different source address than the one it sent the query to. The + client would fall back on TCP after several attempts, which works + well in this situation, but it is clearly not ideal. + + + There are plans to solve the problem in a way the server will handle + it itself. But until it is actually implemented, it is recommended to + alter the configuration — remove the wildcard addresses and list all + addresses explicitly. Then the server will answer on the same + interface as the request came, preserving the correct address. + +