Man page or keyword search:   man All Sections 1 - General Commands 2 - System Calls 3 - Subroutines, Functions 4 - Special Files 5 - File Formats 6 - Games and Screensavers 7 - Macros and Conventions 8 - Maintenence Commands 9 - Kernel Interface New Commands Server 4.4BSD AIX Alpinelinux Archlinux Aros BSDOS BSDi Bifrost CentOS Cygwin Darwin Debian DigitalUNIX DragonFly ElementaryOS Fedora FreeBSD Gentoo GhostBSD HP-UX Haiku Hurd IRIX Inferno JazzOS Kali Knoppix LinuxMint MacOSX Mageia Mandriva Manjaro Minix MirBSD NeXTSTEP NetBSD OPENSTEP OSF1 OpenBSD OpenDarwin OpenIndiana OpenMandriva OpenServer OpenSuSE OpenVMS Oracle PC-BSD Peanut Pidora Plan9 QNX Raspbian RedHat Scientific Slackware SmartOS Solaris SuSE SunOS Syllable Tru64 UNIXv7 Ubuntu Ultrix UnixWare Xenix YellowDog aLinux   14857 pages apropos Keyword Search (all sections) Output format html ascii pdf view pdf save postscript

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
       · 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  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.

       · 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@ms2.inr.ac.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-rout‐
       ing/iputils-current.tar.gz.

iputils-021109			09 ������ 2002			  CLOCKDIFF(8)

Vote for polarhome