NAME

       dnsreplay - A PowerDNS nameserver debugging tool

SYNOPSIS

       dnsreplay [OPTION]... FILENAME ADDRESS [PORT]

DESCRIPTION

       This  program  takes  recorded  questions  and  answers  and replays them to the specified nameserver and
       reporting afterwards which percentage of answers matched, were worse or better.

       dnsreplay compares the answers and some other metrics with the  actual  ones  with  those  found  in  the
       dumpfile.

       By default it only replay queries with recursion-desired flag set.

OPTIONS

       FILENAME
              is  expected  to  be an PCAP file. The queries are send to the DNS server specified as ADDRESS and
              PORT.

       ADDRESS
              IPv4 or IPv6 address of the nameserver to replay FILENAME to.

       PORT   if omitted, 53 will be used.

       --help, -h
              Show summary of options.

       --ecs-mask <VAL>
              When EDNS forwarding an IP address, mask out first octet with this value

       --ecs-stamp <FLAG>
              Add original IP address as EDNS Client Subnet Option when forwarding to reference server

       --packet-limit <NUM>
              Stop after replaying NUM packets. Default for NUM is 0, which means no limit.

       --pcap-dns-port <VAL>
              Look at packets from or to this port in the PCAP. Default is 53.

       --quiet <FLAG>
              If FLAG is set to 1. dnsreplay will not be very noisy with its output. This is the default.

       --recursive <FLAG>
              If FLAG is set to 1. dnsreplay will only replay queries with recursion desired flag set.  This  is
              the default.

       --source-from-pcap <FLAG>
              If  FLAG is set to 1. dnsreplay will send the replayed queries from the source IP address and port
              present in the PCAP file. This requires IP_TRANSPARENT support. Default is 0 which means  replayed
              queries will be sent from a local address.

       --source-ip <VAL>
              Send  the  replayed  queries  from  the source IP specified in VAL. Default is to send them from a
              local address.

       --source-port <VAL>
              Send the replayed queries from the source port specified in VAL.  Default is to send from a random
              port selected by the kernel.

       --speedup <FACTOR>
              Replay queries with this speedup FACTOR. Default is 1.

       --timeout-msec <MSEC>
              Wait at least MSEC milliseconds for a reply. Default is 500.

BUGS

       dnsreplay has no certain handling for timeouts. It handles around at most 65536 outstanding answers.

SEE ALSO

       pcap(3PCAP), tcpdump(8), dnswasher(1)

AUTHOR

       PowerDNS.COM BV

COPYRIGHT

       PowerDNS.COM BV

                                                  Jul 07, 2025                                      DNSREPLAY(1)