NAME

       sc_ally — scamper driver to run Ally on a list of candidate aliases.

SYNOPSIS

       sc_ally [-?D] [-a infile] [-o outfile] [-p port] [-U unix-socket] [-f fudge] [-i probe-wait] [-O options]
               [-q attempts] [-t logfile] [-w waittime]

       sc_ally [-d dump-id] [-O options] [file ...]

DESCRIPTION

       The  sc_ally  utility  provides the ability to connect to a running scamper(1) instance and have a set of
       IPv4 address-pairs tested for aliases using the Ally technique.  For  each  address  pair  in  the  file,
       sc_ally  establishes  which  probe methods (UDP, TCP-ack, ICMP-echo) solicit an incrementing IP-ID value,
       and then uses the Ally technique on pairs where a probe method is able to obtain  an  incrementing  IP-ID
       for  both  addresses.   sc_ally  can  also infer which IP addresses are aliases using the Mercator common
       source address technique as a byproduct of the UDP probing that sc_ally does.  The output of  sc_ally  is
       written to a warts(5) file, which can then be processed to extract aliases.  The options are as follows:

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

       -D      causes sc_ally to detach and become a daemon.

       -a infile
               specifies the name of the input file which consists of a sequence of IPv4 address-pairs, one pair
               per line.

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

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

       -U unix-socket
               specifies  the  name  of  a  unix  domain  socket  where  scamper(1)  is accepting control socket
               connections.

       -d dump-id
               specifies the number identifying an analysis to conduct.  The current choices for  are  1-3,  and
               are:
                 -  1: dump aliases inferred using the Ally (IPID-based) technique.
                 -  2: dump aliases inferred using the Mercator (common source address based) technique.
                 -  3: dump aliases inferred using both Ally and Mercator techniques.

       -f fudge
               specifies  the  fudge  factor to use when (1) inferring if IPIDs are assigned from a counter, and
               (2) inferring if two addresses share the same counter.

       -i probe-wait
               specifies the inter-probe gap for both ping and Ally measurements, in milliseconds.  The  default
               is 1000ms (1 second); the minimum is 200ms, and the maximum is 2000ms.

       -O options
               allows the behavior of sc_ally to be further tailored.  The current choices for this option are:
                 -  nobs:  do  not  consider byte swapped IPID values when inferring if IPID values are assigned
                    from a counter.
                 -  tc: dump transitive closure when reporting aliases.

       -q attempts
               specifies the number of times to try Ally when one of the addresses is unresponsive.

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

       -w waittime
               specifies the minimum length of time, in seconds, to wait between completing a measurement  to  a
               particular IP address and issuing the next.

EXAMPLES

       Given a set of IPv4-address pairs in a file named infile.txt:

          192.0.2.1 192.0.32.10
          192.0.2.2 192.0.31.8
          192.0.2.3 192.0.30.64

       and a scamper(1) daemon listening on port 31337, then these address-pairs can be tested for aliases using

       sc_ally -i infile.txt -o outfile.warts -p 31337

       To obtain a list of inferred alias pairs using the Ally technique from a warts(5) file:

       sc_ally -d 1 outfile.warts

       To  obtain  a  list of inferred routers using a transitive closure of alias pairs inferred using the Ally
       and Mercator techniques:

       sc_ally -d 3 -O tc outfile.warts

SEE ALSO

       scamper(1), sc_radargun(1), sc_wartsdump(1), sc_warts2text(1),

       N. Spring, R. Mahajan, and D. Wetherall, Measuring ISP topologies  with  Rocketfuel,  Proc.  ACM  SIGCOMM
       2002.

       R. Govindan and H. Tangmunarunkit, Heuristics for Internet Map Discovery, Proc. IEEE INFOCOM 2000.

       A.  Bender,  R.  Sherwood,  and  N.  Spring,  Fixing  Ally's  growing pains with velocity modeling, Proc.
       ACM/SIGCOMM Internet Measurement Conference 2008.

AUTHORS

       sc_ally was written by Matthew Luckie <mjl@luckie.org.nz>.

Debian                                          December 22, 2016                                     SC_ALLY(1)