Ertuğrul Erata
82 lines
2.4 KiB
Plaintext
82 lines
2.4 KiB
Plaintext
.\" This manpage has been automatically generated by docbook2man
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.\" from a DocBook document. This tool can be found at:
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.\" <http://shell.ipoline.com/~elmert/comp/docbook2X/>
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.\" Please send any bug reports, improvements, comments, patches,
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.\" etc. to Steve Cheng <steve@ggi-project.org>.
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.TH "CLOCKDIFF" "8" "24 Mayıs 2011" "iputils-101006" "System Manager's Manual: iputils"
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.SH NAME
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clockdiff \- measure clock difference between hosts
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.SH SYNOPSIS
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\fBclockdiff\fR [ \fB-o\fR] [ \fB-o1\fR] \fB\fIdestination\fB\fR
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.SH "DESCRIPTION"
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.PP
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\fBclockdiff\fR Measures clock difference between us and
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\fIdestination\fR with 1 msec resolution using ICMP TIMESTAMP
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[2]
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packets or, optionally, IP TIMESTAMP option
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[3]
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option added to ICMP ECHO.
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[1]
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.SH "OPTIONS"
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.TP
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\fB-o\fR
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Use IP TIMESTAMP with ICMP ECHO instead of ICMP TIMESTAMP
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messages. It is useful with some destinations, which do not support
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ICMP TIMESTAMP (f.e. Solaris <2.4).
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.TP
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\fB-o1\fR
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Slightly different form of \fB-o\fR, namely it uses three-term
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IP TIMESTAMP with prespecified hop addresses instead of four term one.
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What flavor works better depends on target host. Particularly,
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\fB-o\fR is better for Linux.
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.SH "WARNINGS"
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.TP 0.2i
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\(bu
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Some nodes (Cisco) use non-standard timestamps, which is allowed
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by RFC, but makes timestamps mostly useless.
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.TP 0.2i
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\(bu
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Some nodes generate messed timestamps (Solaris>2.4), when
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run \fBxntpd\fR. Seems, its IP stack uses a corrupted clock source,
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which is synchronized to time-of-day clock periodically and jumps
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randomly making timestamps mostly useless. Good news is that you can
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use NTP in this case, which is even better.
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.TP 0.2i
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\(bu
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\fBclockdiff\fR shows difference in time modulo 24 days.
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.SH "SEE ALSO"
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.PP
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\fBping\fR(8),
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\fBarping\fR(8),
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\fBtracepath\fR(8).
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.SH "REFERENCES"
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.PP
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[1] ICMP ECHO,
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RFC0792, page 14.
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.PP
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[2] ICMP TIMESTAMP,
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RFC0792, page 16.
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.PP
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[3] IP TIMESTAMP option,
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RFC0791, 3.1, page 16.
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.SH "AUTHOR"
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.PP
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\fBclockdiff\fR was compiled by
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Alexey Kuznetsov
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<kuznet@ms2.inr.ac.ru>. It was based on code borrowed
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from BSD \fBtimed\fR daemon.
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It is now maintained by
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YOSHIFUJI Hideaki
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<yoshfuji@skbuff.net>.
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.SH "SECURITY"
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.PP
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\fBclockdiff\fR requires CAP_NET_RAWIO capability
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to be executed. It is safe to be used as set-uid root.
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.SH "AVAILABILITY"
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.PP
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\fBclockdiff\fR is part of \fIiputils\fR package
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and the latest versions are available in source form at
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http://www.skbuff.net/iputils/iputils-current.tar.bz2.
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