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       tcpblast - tool for measuring network bandwidth


       tcpblast [options] destination[:port]


       tcpblast/udpblast is a simple tool for probing network and estimating
       its throughput. By default it sends 300 blocks (1024 bytes each) of
       data to specified destination host.

       Destination can be name or address, IPv4 or IPv6. When IPv6 address is
       specified with port it should look like: ’[3ffe:8010::1]:9’ (with
       single quotes to prevent shell expansion of []).


       -4, --ipv4           use only ipv4 address

       -6, --ipv6           use only ipv6 address

       -a                   send random data

       -b BUF_SIZE          socket buf size (default: -1, don’t change), with
       ‘-’ to be substracted from results

       -c, --count BLOCKS   change default (300) number of blocks, range:

       -d DOTFREQ           print dot every DOTFREQ blocks, disables cont.
       speed disp.

       -h, --help           this help

       -i, --delay DELAY    write delay in microseconds (EXPERIMENTAL)

       -l, --last BLKS      show also speed for last BLKS blocks

       -m                   results for every block in separate line

       -n, --nwrite         do not write, use e.g. with chargen port

       -o                   switch from continuous speed displaying to dots

       -p PORT              bind this local PORT

       -q --quiet           show only final statistics

       -r, --read           read data returned to us, switches default port to

       -R, --rate RATESPEC  limit the speed according to the RATESPEC

       -s BLOCK_SIZE        block size (default 1024 bytes)

       -t MAXTIME           limit time to MAXTIME (up to 42950 h)

           --tcp            use TCP (default)

           --udp            use UDP (default if named udpblast)

       -v, --verbosity      verbosity, default 0, maximum 3. -v adds time
       display, -vv also speed in B/s, -v - speed in b/s.

       -V, --version        version

       destination          host name or address

       port                 use port #/name xyz instead of default port 9

       RATESPEC         RATE[,TIME][:RATE[,TIME]]...  RATE
       generating data at RATE speed in B/s TIME             for TIME seconds
       (can be floating point number), last can
                          be omitted and that time will be infinite

       Options -b, -c, -R, -s and -t can use case insensitive unit multipliers
       and specifiers:
         size (bytes):
           -b and -s argument without units is in bytes, can use [{k,m,g}]b
           or upper case) for KB, MB or GB. {k,m,g} are powers of 1024.
           -c argument is just a number, can have k, m or g added (powers of
           no unit needed
         rate (bytes pes second):
           -R RATE is in B/s or Bps, the postfixes can be [{k,m,g}]{b/s,bps}
         time (seconds):
           -t and -R TIME argument is in seconds, can be postfixed with

         tcpblast -b 4KB -c 10k -R 10kbps,2:20kbps,3s target

       tcpblast version: FreeBSD + rzm 20001030


       Rafal says that he is a perfectly bad and careless maintainer  :)

       If You found any other bugs send it to him.


       Software: (Daniel Karrenberg - acc. to FreeBSD version)

       Maintained by: Rafal Maszkowski <>

       Manual page: Artur R. Czechowski <>, Oct 1999; rzm,
       Oct 2000