CLOCKDIFF(8) System Manager's Manual: iputils CLOCKDIFF(8)
clockdiff - measure clock difference between hosts
clockdiff [-o] [-o1] destination
clockdiff Measures clock difference between us and destination with 1 msec resolution using ICMP TIMESTAMP  packets or, optionally, IP TIMESTAMP option  option added to ICMP ECHO. 
-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 better depends on target host. Particularly, -o is better for Linux.
· 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.
ping(8), arping(8), tracepath(8).
 ICMP ECHO, RFC0792, page 14.  ICMP TIMESTAMP, RFC0792, page 16.  IP TIMESTAMP option, RFC0791, 3.1, page 16.
clockdiff was compiled by Alexey Kuznetsov <firstname.lastname@example.org>. It was based on code borrowed from BSD timed daemon. It is now maintained by YOSHIFUJI Hideaki <email@example.com>.
clockdiff requires CAP_NET_RAW capability to be executed. It is safe to be used as set-uid root.
clockdiff is part of iputils package and the latest versions are available in source form at http://www.skbuff.net/iputils/iputils-current.tar.bz2.
This page is part of the iputils (IP utilities) project. Information about the project can be found at ⟨http://www.skbuff.net/iputils/⟩. If you have a bug report for this manual page, send it to firstname.lastname@example.org, email@example.com. This page was obtained from the project's upstream Git repository ⟨git://git.linux-ipv6.org/gitroot/iputils.git⟩ on 2017-04-25. If you discover any rendering problems in this HTML version of the page, or you believe there is a better or more up-to-date source for the page, or you have corrections or improvements to the information in this COLOPHON (which is not part of the original manual page), send a mail to firstname.lastname@example.org iputils-151218 25 April 2017 CLOCKDIFF(8)
Pages that refer to this page: arping(8)