README

   1                                     This is NetGrind 1.1
   2
   3                               (c) 2003 Martin Mares <mj@ucw.cz>
   4
   5 This software can be freely distributed and used according to the GNU General Public License.
   6 ---------------------------------------------------------------------------------------------
   7
   8 What's that?
   9 ~~~~~~~~~~~~
  10
  11 NetGrind is an experimental tool for analysing network traffic. It processes packet dumps
  12 captured by tcpdump (or any other libpcap application) and it's able to do:
  13
  14    o  Filtering of data by using libpcap filters.
  15    o  TCP demultiplexing and dumping of demultiplexed data to files
  16    o  Calculating per-connection TCP statistics
  17    o  Analysing HTTP connections and demultiplexing them to individual transactions,
  18       calculating statistics for each transaction.
  19
  20 Although some of the analysis modes are available through command-line switches,
  21 NetGrind still misses a powerful configuration language, so the more advanced features
  22 like analysing HTTP must be configured (and bound to the right addresses and ports)
  23 by modifying the source, namely the mux_open() function which gets called for each
  24 newly established TCP connection when no command-line switches are given. The example
  25 in our source just connects HTTP analyser to all TCP connections to ports 80, 8080, 8081
  26 and 3128 and ignores the rest.
  27
  28 You will also find a couple of postprocessing tools in the "post" directory.
  29
  30
  31 TCP report syntax:
  32 ~~~~~~~~~~~~~~~~~~
  33
  34                                                                                                     +--- TCP overhead
  35                                                                                     bytes  bytes    |
  36                         source address:port   destination addr:port                 sent   received |      +--- KB/s (RX+TX)
  37                           |                     |                                     |       |     |      |
  38 2003-06-06 22:38:34.076 81.27.194.19:1165     195.113.31.123:22          1.604 OK    1991   12656  11%  8.914
  39   |                                                                       |    |
  40 date and time of first SYN                                      elapsed time  termination status:  OK = closed with FIN
  41                                                                                                    RE = connection reset
  42                                                                                                    TO = timeout (maybe miscaptured)
  43                                                                                                    DD = doomsday (cut by end of capture)
  44                                                                                                    CO = corrupted (protocol violation)
  45
  46
  47
  48 HTTP report syntax:
  49 ~~~~~~~~~~~~~~~~~~~
  50
  51
  52                                          data transmitted in both directions (excluding headers) ----+
  53                                                                                                      |   response delay ---+
  54                                                           transaction # on this connection ---+      |       [sec]         |
  55                                                                                               |      |                     |   method and
  56                                                                           cache status --+    |      |   duration [sec]    |   request URI
  57                         source address:port   destination addr:port                      |    |      |         |           |    |
  58                           |                     |                                        |    |      |         |           |    |
  59 2003-06-06 22:53:38.642 81.27.194.19:1175     205.217.153.53:80     123.123.123.123 200 ...   0    14030      0.957      0.444 GET http://...
  60   |                                                                        |         |
  61 date and time of request start                                   X-Forwarded-For    HTTP response code or
  62 (if it's the first request on a connection,                                         ERR = HTTP violation
  63 it's the time where the connection was initiated,                                   CUT = connection closed before transaction finish
  64 even if the request has been transmitted later)                                     FIN = CONNECT request finished by connection close
  65                                                                                     Txx = TCP error xx (see above)
  66
  67 Cache status codes:
  68
  69         1st char: request cacheing control      . = none
  70                                                 N = don't cache
  71                                                 R = revalidate
  72         2nd char: response cacheability         . = not restricted
  73         (first matching letter used)            N = don't cache
  74                                                 P = private
  75                                                 S = don't store to non-volatile storage
  76                                                 R = must be revalidated
  77         3rd char: cache response                . = X-Cache not found
  78         (X-Cache header, optional)              - = MISS
  79                                                 + = HIT
  80                                                 ? = other