CLOCKDIFF - 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 resolu-
       tion 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 messages. 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 bet-
              ter depends on target host. Particularly, -o is better for Linux.

WARNINGS
       · Some  nodes  (Cisco)  use  non-standard  timestamps, which is allowed by RFC, but
         makes timestamps mostly useless.

       · Some nodes generate messed timestamps (Solaris>2.4), when run xntpd.  Seems,  its
         IP  stack  uses  a  corrupted  clock source, which is synchronized 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.

       · 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.

SECURITY
       clockdiff requires CAP_NET_RAWIO 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   for   anonymous   ftp   ftp://ftp.inr.ac.ru/ip-routing/iputils-cur-
       rent.tar.gz.



iputils-020927                   07 April 2005                    CLOCKDIFF(8)

Generated by $Id: phpMan.php,v 4.55 2007/09/05 04:42:51 chedong Exp $ Author: Che Dong
On Apache/1.3.41 (Unix) PHP/5.2.5 mod_perl/1.30 mod_gzip/1.3.26.1a
Under GNU General Public License
2008-11-22 07:11 @38.103.63.58 CrawledBy CCBot/1.0 (+http://www.commoncrawl.org/bot.html)