clockdiff(8) - phpMan

CLOCKDIFF(8)           System Manager's Manual: iputils           CLOCKDIFF(8)

NAME
       clockdiff - measure clock difference between hosts
SYNOPSIS
       clockdiff [-o] [-o1] destination

DESCRIPTION
       clockdiff  Measures  clock difference between us and destination with 1
       msec resolution using ICMP TIMESTAMP [2]  packets  or,  optionally,  IP
       TIMESTAMP option [3] option added to ICMP ECHO.  [1]
OPTIONS
       -o     Use  IP  TIMESTAMP with ICMP ECHO instead of ICMP TIMESTAMP mes-
              sages. It is useful with some destinations, which do not support
              ICMP TIMESTAMP (f.e. Solaris <2.4).
       -o1    Slightly  different  form  of  -o,  namely it uses three-term IP
              TIMESTAMP with prespecified hop addresses instead of  four  term
              one.   What flavor works better depends on target host. Particu-
              larly, -o is better for Linux.
WARNINGS
       o Some nodes (Cisco) use non-standard timestamps, which is  allowed  by
         RFC, but makes timestamps mostly useless.
       o Some  nodes generate messed timestamps (Solaris>2.4), when run xntpd.
         Seems, its IP stack uses a corrupted clock source, which is  synchro-
         nized  to  time-of-day  clock  periodically and jumps randomly making
         timestamps mostly useless. Good news is that you can use NTP in  this
         case, which is even better.
       o clockdiff shows difference in time modulo 24 days.
SEE ALSO
       ping(8), arping(8), tracepath(8).
REFERENCES
       [1] ICMP ECHO, RFC0792, page 14.
       [2] ICMP TIMESTAMP, RFC0792, page 16.
       [3] IP TIMESTAMP option, RFC0791, 3.1, page 16.
AUTHOR
       clockdiff  was  compiled by Alexey Kuznetsov <kuznet AT ms2.ru>. It
       was based on code borrowed from BSD timed daemon.  It is now maintained
       by YOSHIFUJI Hideaki <yoshfuji AT skbuff.net>.
SECURITY
       clockdiff requires CAP_NET_RAW capability to be executed. It is safe to
       be used as set-uid root.
AVAILABILITY
       clockdiff is part of  iputils  package  and  the  latest  versions  are
       available  in source form at http://www.skbuff.net/iputils/iputils-cur-
       rent.tar.bz2.

iputils-160308                                                    CLOCKDIFF(8)