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- .\" This manpage has been automatically generated by docbook2man
- .\" from a DocBook document. This tool can be found at:
- .\" <http://shell.ipoline.com/~elmert/comp/docbook2X/>
- .\" Please send any bug reports, improvements, comments, patches,
- .\" etc. to Steve Cheng <steve@ggi-project.org>.
- .TH "CLOCKDIFF" "8" "24 Mayıs 2011" "iputils-101006" "System Manager's Manual: iputils"
- .SH NAME
- clockdiff \- measure clock difference between hosts
- .SH SYNOPSIS
- \fBclockdiff\fR [ \fB-o\fR] [ \fB-o1\fR] \fB\fIdestination\fB\fR
- .SH "DESCRIPTION"
- .PP
- \fBclockdiff\fR Measures clock difference between us and
- \fIdestination\fR with 1 msec resolution using ICMP TIMESTAMP
- [2]
- packets or, optionally, IP TIMESTAMP option
- [3]
- option added to ICMP ECHO.
- [1]
- .SH "OPTIONS"
- .TP
- \fB-o\fR
- 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).
- .TP
- \fB-o1\fR
- Slightly different form of \fB-o\fR, 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,
- \fB-o\fR is better for Linux.
- .SH "WARNINGS"
- .TP 0.2i
- \(bu
- Some nodes (Cisco) use non-standard timestamps, which is allowed
- by RFC, but makes timestamps mostly useless.
- .TP 0.2i
- \(bu
- Some nodes generate messed timestamps (Solaris>2.4), when
- run \fBxntpd\fR. 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.
- .TP 0.2i
- \(bu
- \fBclockdiff\fR shows difference in time modulo 24 days.
- .SH "SEE ALSO"
- .PP
- \fBping\fR(8),
- \fBarping\fR(8),
- \fBtracepath\fR(8).
- .SH "REFERENCES"
- .PP
- [1] ICMP ECHO,
- RFC0792, page 14.
- .PP
- [2] ICMP TIMESTAMP,
- RFC0792, page 16.
- .PP
- [3] IP TIMESTAMP option,
- RFC0791, 3.1, page 16.
- .SH "AUTHOR"
- .PP
- \fBclockdiff\fR was compiled by
- Alexey Kuznetsov
- <kuznet@ms2.inr.ac.ru>. It was based on code borrowed
- from BSD \fBtimed\fR daemon.
- It is now maintained by
- YOSHIFUJI Hideaki
- <yoshfuji@skbuff.net>.
- .SH "SECURITY"
- .PP
- \fBclockdiff\fR requires CAP_NET_RAWIO capability
- to be executed. It is safe to be used as set-uid root.
- .SH "AVAILABILITY"
- .PP
- \fBclockdiff\fR is part of \fIiputils\fR package
- and the latest versions are available in source form at
- http://www.skbuff.net/iputils/iputils-current.tar.bz2.
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