NAME

       dnstcpbench - tool to perform TCP benchmarking of nameservers

SYNOPSIS

       dnstcpbench [OPTION]...  REMOTE-ADDRESS [REMOTE-PORT]

DESCRIPTION

       dnstcpbench  reads  DNS  queries  (by  default  from standard input) and sends them out in
       parallel to a remote nameserver.  By default TCP/IP is used, but optionally, UDP is  tried
       first, which allows for the benchmarking of TCP/IP fallback.

       The  program  reports  both mean and median numbers for queries per second and UDP and TCP
       latency.  Each query only counts  once,  even  if  it  is  tried  over  UDP  first.   This
       effectively  means  that passing '-u' can lower query rates if many queries get shunted to
       TCP.

       The input format is one query per line: qname single-space qtype.  An example:

       www.powerdns.com ANY

       When benchmarking extended runs, it may be necessary to  enable  TIME_WAIT  recycling,  as
       TCP/IP port tuples may otherwise run out.  On Linux this is performed by running:

       echo 1 > /proc/sys/net/ipv4/tcp_tw_recycle

       The equivalent for IPv6 is not known.

OPTIONS

       -f | --file FILENAME
              FILENAME from which to read queries.  Defaults to standard input if unspecified.

       -h | --help
              Provide a helpful message.

       --timeout-msec MSEC
              MSEC milliseconds to wait for an answer.

       -u | --udp-first
              Attempt resolution via UDP first, only do TCP if truncated answer is received.

       -v | --verbose
              Be wordy on what the program is doing.

       --workers NUM
              Use NUM parallel worker threads.

       REMOTE-ADDRESS
              IPv4 or IPv6 to test against.

       REMOTE-PORT
              Port to test against, defaults to 53.

BUGS

       Currently  the timeout code does not actually perform non-blocking connects or writes.  So
       a slow connect or slow writes will still cause low performance and delays.

       Median queries per second statistics are reported as 0 for sub-second runs.

AUTHORS

       PowerDNS.COM BV.

                                            July 2013                              DNSTCPBENCH(1)