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] [clockdiff(8)] packets or, optionally, IP TIMESTAMP option [3] [clockdiff(8)] option added to ICMP ECHO. [1] [clockdiff(8)]

OPTIONS

\FC-o\F[]
    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).

\FC-o1\F[]
    Slightly different form of \FC-o\F[], 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, \FC-o\F[] 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 (Solaris2.4), 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)[Cross reference to non-existant ID “ping”], arping(8)[Cross reference to non-existant ID “arping”], tracepath(8)[Cross reference to non-existant ID “tracepath”].

REFERENCES
[1]

[2]

[3]

AUTHOR
clockdiff was compiled by . It was based on code borrowed from BSD timed daemon. It is now maintained by .

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 \FCiputils\F[] package and the latest versions are available in source form at ⟨http://www.skbuff.net/iputils/iputils-current.tar.bz2⟩.