clockdiff - measure clock difference between hosts
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. 
- 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).
- 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
 ICMP ECHO, RFC0792, page 14.
 ICMP TIMESTAMP, RFC0792, page 16.
 IP TIMESTAMP option, RFC0791, 3.1, page 16.
was compiled by Alexey Kuznetsov <email@example.com>.
It was based on code borrowed from BSD timed
daemon. It is now
maintained by YOSHIFUJI Hideaki <firstname.lastname@example.org>.
requires CAP_NET_RAW capability to be executed. It is safe to
be used as set-uid root.
is part of iputils
package and the latest versions are
available in source form at