g. eth0) to use
The first step is to start up a receiver process on the server machine:
# ttcp -rs
ttcp-r: buflen=8192, nbuf=2048, align=16384/0, port=5001 tcp
ttcp-r: socket
The ??“r flag denotes that the server machine will be the receiver. The ??“s flag, in conjunction with
the ??“r flag, tells ttcp that you want to ignore any received data.
The next step is to have someone outside of your data link, with a network link close to the same
speed as yours, set up a ttcp sending process:
# ttcp -ts server.example.com
ttcp-t: buflen=8192, nbuf=2048, align=16384/0, port=5001 tcp
-> server.example.com
ttcp-t: socket
ttcp-t: connect
Let the process run for a few minutes and then press Ctrl+C on the transmitting side to stop the
testing. The receiving side then takes a moment to calculate and present the results:
# ttcp -rs
ttcp-r: buflen=8192, nbuf=2048, align=16384/0, port=5001 tcp
ttcp-r: socket
ttcp-r: accept from 64.223.17.21
ttcp-r: 2102496 bytes in 70.02 real seconds = 29.32 KB/sec +++
ttcp-r: 1226 I/O calls, msec/call = 58.49, calls/sec = 17.51
ttcp-r: 0.0user 0.0sys 1:10real 0% 0i+0d 0maxrss 0+2pf 0+0csw
In this example, the average bandwidth between the two hosts was 29.32 kilobytes per second. On
a link suffering from a DDOS, this number would be a mere fraction of the actual bandwidth the
data link is rated for.
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