clockdiff man page

clockdiff ā€” 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 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.

Warnings

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_RAW capability to be executed. It is safe to be used as set-uid root.

Availability

clockdiff is part of iputils package.

Referenced By

arping(8).

iputils s20180629