Question

We consider Host-A initiates a failed TCP session to Host-B if the following two conditions are satisfied: 1. Host-A sends a SYN packet to Host-B (to initiate a new TCP session); 2. Host-B sends no packet to Host-A or only RST packet(s) (for this session). For all IRC clients observed in this trace, does any of them initiate more than 10 failed connections? If so, please show their IP addresses and evidence. What commands are needed in WIRESHARK to complete this task.

Answer 1

Usage: wireshark [options] ... [ <infile> ]

Capture interface:
  -i <interface>           name or idx of interface (def: first non-loopback)
  -f <capfilter|predef:>   packet filter in libpcap filter syntax or
                           predef:filtername - predefined filtername from GUI
  -s <snaplen>             packet snapshot length (def: 262144)
  -p                       don’t capture in promiscuous mode
  -k                       start capturing immediately (def: do nothing)
  -S                       update packet display when new packets are captured
  -l                       turn on automatic scrolling while -S is in use
  -I                       capture in monitor mode, if available
  -B <buffer size>         size of kernel buffer (def: 2MB)
  -y <link type>           link layer type (def: first appropriate)
  --time-stamp-type <type> timestamp method for interface
  -D                       print list of interfaces and exit
  -L                       print list of link-layer types of iface and exit
  --list-time-stamp-types  print list of timestamp types for iface and exit

Capture stop conditions:
  -c <packet count>        stop after n packets (def: infinite)
  -a <autostop cond.> ...  duration:NUM - stop after NUM seconds
                           filesize:NUM - stop this file after NUM KB
                              files:NUM - stop after NUM files
Capture output:
  -b <ringbuffer opt.> ... duration:NUM - switch to next file after NUM secs
                           filesize:NUM - switch to next file after NUM KB
                              files:NUM - ringbuffer: replace after NUM files
RPCAP options:
  -A <user>:<password>     use RPCAP password authentication
Input file:
  -r <infile>              set the filename to read from (no pipes or stdin!)

Processing:
  -R <read filter>         packet filter in Wireshark display filter syntax
  -n                       disable all name resolutions (def: all enabled)
  -N <name resolve flags>  enable specific name resolution(s): "mnNtdv"
  -d <layer_type>==<selector>,<decode_as_protocol> ...
                           "Decode As”, see the man page for details
                           Example: tcp.port==8888,http
  --disable-protocol <proto_name>
                           disable dissection of proto_name
  --enable-heuristic <short_name>
                           enable dissection of heuristic protocol
  --disable-heuristic <short_name>
                           disable dissection of heuristic protocol

User interface:
  -C <config profile>      start with specified configuration profile
  -Y <display filter>      start with the given display filter
  -g <packet number>       go to specified packet number after "-r"
  -J <jump filter>         jump to the first packet matching the (display)
                           filter
  -j                       search backwards for a matching packet after "-J"
  -m <font>                set the font name used for most text
  -t a|ad|d|dd|e|r|u|ud    output format of time stamps (def: r: rel. to first)
  -u s|hms                 output format of seconds (def: s: seconds)
  -X <key>:<value>         eXtension options, see man page for details
  -z <statistics>          show various statistics, see man page for details

Output:
  -w <outfile|->           set the output filename (or '-' for stdout)

Miscellaneous:
  -h                       display this help and exit
  -v                       display version info and exit
  -P <key>:<path>          persconf:path - personal configuration files
                           persdata:path - personal data files
  -o <name>:<value> ...    override preference or recent setting
  -K <keytab>              keytab file to use for kerberos decryption