Merge pull request #376 from hills/master

Point the user towards tcpdump for logging individual queries

doc/manual/running/logging.rst

@@ -7,6 +7,11 @@ in order to keep NSD focused and minimise its complexity.
 It is better to leave logging and tracing to separate dedicated tools. Do note,
 however, that NSD can be compiled with support for DNSTAP (see ``nsd.conf(5)``).
 
+If some visibility on individual queries is required, consider running
+``tcpdump(1)`` on the server, using an appropriate filter rule to capture UDP
+and TCP packets to port 53. The tcpdump on most systems will decode the packets
+into readable requests and responses.
+
 The `CAIDA dnsstat tool <https://www.caida.org/catalog/software/dnsstat/>`_ can
 easily be configured and/or modified to suit local statistics requirements
 without any danger of affecting the name server itself. We have run ``dnsstat``