NAME

       sc_tbitpmtud — scamper driver to test systems for responsiveness to ICMP packet too big messages

SYNOPSIS

       sc_tbitpmtud      [-r]      [-a     address-file]     [-c     completed-file]     [-l     limit-per-file]
                    [-m maximum-transmission-unit] [-o output-file] [-p scamper-port] [-t log-file] [-w window]

       sc_tbitpmtud [-d dump-id] [-A ip2as-file] [-m maximum-transmission-unit] [file ...]

DESCRIPTION

       The sc_tbitpmtud utility provides the ability to connect to a running scamper(1) instance  and  use  that
       instance  to test end systems for their ability to perform Path MTU Discovery, with the output written to
       a file in warts format.  sc_tbitpmtud first tests a given system for responsiveness to ICMP echo packets,
       and then tests the given system's TCP stack response to ICMP packet too big messages.

       The options are as follows:

       -?      prints a list of command line options and a synopsis of each.

       -a address-file
               specifies the name of the input file which consists of a sequence of systems to test, one  system
               per line.

       -A ip2as-file
               specifies  the  name  of  a  file which consists of a mapping of prefixes to ASes, one prefix per
               line.

       -c completed-file
               specifies the name of a file to record IP addresses that have been tested.

       -d dump-id
               specifies the dump ID to use to analyze the collected data.  Currently, ID values 1  (mssresults)
               and  2  (asnresults) are valid, which report PMTUD behaviour according to the server's MSS or the
               server's origin ASN.

       -l limit-per-file
               specifies the number of tbit objects to record per warts file, before  opening  a  new  file  and
               placing new objects.

       -m maximum transmission unit
               specifies  the  pseudo  maximum transmission unit to use.  The available choices are 0, 256, 576,
               1280, 1480.  If 0 is chosen, sc_tbitpmtud will test each website with all available  MTU  choices
               in decreasing size.  The default MTU value tested is 1280.

       -o output-file
               specifies the name of the file to be written.  The output file will use the warts format.

       -p scamper-port
               specifies the port on the local host where scamper(1) is accepting control socket connections.

       -r      shuffle the order in which websites are tested.

       -t log-file
               specifies the name of a file to log progress output from sc_tbitpmtud generated at run time.

       -w window-size
               specifies  the  maximum number of tests to conduct in parallel.  The window size value depends on
               the value of the -F parameter passed to the scamper(1) instance.

EXAMPLES

       Use of this driver requires a scamper(1) instance listening on a port  for  commands  with  a  configured
       firewall.   The  following  invocation  uses ipfw(8) firewall rules 1 to 100, with a corresponding window
       size of 100, and an unrestricted packets per second rate, as follows:

             scamper -P 31337 -F ipfw:1-100 -w 100 -p 0

       To test a set of web servers specified in a file named webservers.txt and formatted as follows:

          1,example.com 5063 192.0.2.1 http://www.example.com/
          1,example.com 5063 2001:DB8::1 http://www.example.com/
          1,example.com 5063 2001:DB8::2 https://www.example.com/

       the following command will test all servers for responsiveness to ICMP packet too big messages and record
       raw data into webservers_00.warts, webservers_01.warts, etc:

             sc_tbitpmtud -a webservers.txt -p 31337 -o webservers

       The webservers.txt file is required to be formatted as above.  The format is: numeric ID to pass to tbit,
       a label for the webserver, the size of the object to be fetched, the IP address to contact, and  the  URL
       to use.

       To characterize PMTUD behaviour according to the server's advertised MSS value:

             sc_tbitpmtud -d mssresults webservers_*.warts

       Given  files  with  IPv4  prefixes  in  prefix2as4.txt  and  IPv6 prefixes in prefix2as6.txt formatted as
       follows:

          2001:DB8::     48     64496
          2001:DB8:1::   48     64497
          192.0.2.0      24     64498

       the following command will characterize PMTUD behaviour according to the origin ASN of the server:

             sc_tbitpmtud -d asnresults -A prefix2as4.txt -A prefix2as6.txt webservers_*.warts

SEE ALSO

       scamper(1), sc_wartsdump(1), sc_warts2json(1), warts(5),

       M. Luckie and  B.  Stasiewicz,  Measuring  Path  MTU  Discovery  Behaviour,  Proc.  ACM/SIGCOMM  Internet
       Measurement Conference 2010.

       A.  Medina,  M. Allman, and S. Floyd, Measuring Interactions between Transport Protocols and Middleboxes,
       Proc. ACM/SIGCOMM Internet Measurement Conference 2004.

AUTHORS

       sc_tbitpmtud was written by Matthew Luckie <mjl@luckie.org.nz>.  Ben Stasiewicz  contributed  an  initial
       implementation of the Path MTU Discovery TBIT test to scamper, building on the work of Medina et al.

Debian                                            March 1, 2018                                  SC_TBITPMTUD(1)