dnsdist: Also handle XFR responses with a lower serial than the query

As suggested by Håkan Lindqvist (thanks!).

diff --git a/pdns/dnsdistdist/dnsdist-tcp-downstream.cc b/pdns/dnsdistdist/dnsdist-tcp-downstream.cc
index ebe795529d5937648d9c30eaee521bbf9507b560..0242841f7fa328b3162f9e967d4c103fc1b72f14 100644 (file)
--- a/pdns/dnsdistdist/dnsdist-tcp-downstream.cc
+++ b/pdns/dnsdistdist/dnsdist-tcp-downstream.cc
@@ -803,7 +803,7 @@ bool TCPConnectionToBackend::isXFRFinished(const TCPResponse& response, TCPQuery
         if (query.d_xfrMasterSerial == 0) {
           // store the first SOA in our client's connection metadata
           query.d_xfrMasterSerial = serial;
-          if (query.d_xfrMasterSerial == query.d_xfrQuerySerial) {
+          if (query.d_xfrMasterSerial <= query.d_xfrQuerySerial) {
             /* This is the first message with a master SOA:
                RFC 1995 Section 2:
                  If an IXFR query with the same or newer version number