{"id":3750,"date":"2022-12-20T17:19:57","date_gmt":"2022-12-20T20:19:57","guid":{"rendered":"http:\/\/lode.uno\/linux-man\/index.php\/2022\/12\/20\/clockdiff-man8\/"},"modified":"2022-12-20T17:19:57","modified_gmt":"2022-12-20T20:19:57","slug":"clockdiff-man8","status":"publish","type":"post","link":"https:\/\/lode.uno\/linux-man\/2022\/12\/20\/clockdiff-man8\/","title":{"rendered":"CLOCKDIFF (man8)"},"content":{"rendered":"

CLOCKDIFF<\/h1>\n

NAME<\/a>
SYNOPSIS<\/a>
DESCRIPTION<\/a>
OPTIONS<\/a>
WARNINGS<\/a>
SEE ALSO<\/a>
REFERENCES<\/a>
AUTHOR<\/a>
SECURITY<\/a>
AVAILABILITY<\/a> <\/p>\n

\n

NAME <\/a> <\/h2>\n

clockdiff \u2212 measure clock difference between hosts<\/p>\n

SYNOPSIS <\/a> <\/h2>\n\n\n
<\/td>\n\n

clockdiff<\/b> [\u2212o<\/b>] [\u2212o1<\/b>] [\u2212\u2212time\u2212format\u00a0<\/b>ctime\u00a0iso<\/i>] [\u2212V<\/b>] {destination}<\/p>\n<\/td>\n<\/tr>\n<\/table>\n

DESCRIPTION <\/a> <\/h2>\n

clockdiff<\/b> Measures clock difference between us and destination<\/i> with 1 msec resolution using ICMP TIMESTAMP [2] packets or, optionally, IP TIMESTAMP option [3] option added to ICMP ECHO. [1]<\/p>\n

OPTIONS <\/a> <\/h2>\n

\u2212o<\/b><\/p>\n

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).<\/p>\n

\u2212o1<\/b><\/p>\n

Slightly different form of \u2212o<\/b>, namely it uses three\u2212term IP TIMESTAMP with prespecified hop addresses instead of four term one. What flavor works better depends on target host. Particularly, \u2212o<\/b> is better for Linux.<\/p>\n

\u2212T<\/b>, \u2212\u2212time\u2212format<\/b> ctime iso<\/i><\/p>\n

Print time stamp in output either ISO\u22128601 format or classical ctime format. The ctime format is default. The ISO time stamp includes timezone, and is easier to parse.<\/p>\n

\u2212I<\/b><\/p>\n

Alias of \u2212\u2212time\u2212format<\/b> iso<\/i> option and argument.<\/p>\n

\u2212h<\/b>, \u2212\u2212help<\/b><\/p>\n

Print help and exit.<\/p>\n

\u2212V<\/b>, \u2212\u2212version<\/b><\/p>\n

Print version and exit.<\/p>\n

WARNINGS <\/a> <\/h2>\n

\u2022 Some nodes (Cisco) use non\u2212standard timestamps, which is allowed by RFC, but makes timestamps mostly useless.<\/p>\n

\u2022 Some nodes generate messed timestamps (Solaris>2.4), when run xntpd<\/b>. Seems, its IP stack uses a corrupted clock source, which is synchronized to time\u2212of\u2212day clock periodically and jumps randomly making timestamps mostly useless. Good news is that you can use NTP in this case, which is even better.<\/p>\n

\u2022 clockdiff<\/b> shows difference in time modulo 24 days.<\/p>\n

SEE ALSO <\/a> <\/h2>\n

ping<\/b>(8), arping<\/b>(8), tracepath<\/b>(8).<\/p>\n

REFERENCES <\/a> <\/h2>\n

[1] ICMP ECHO, RFC0792, page 14.<\/p>\n

[2] ICMP TIMESTAMP, RFC0792, page 16.<\/p>\n

[3] IP TIMESTAMP option, RFC0791, 3.1, page 16.<\/p>\n

AUTHOR <\/a> <\/h2>\n

clockdiff<\/b> was compiled by Alexey Kuznetsov . It was based on code borrowed from BSD timed<\/b> daemon.<\/p>\n

SECURITY <\/a> <\/h2>\n

clockdiff<\/b> requires CAP_NET_RAW capability to be executed. It is safe to be used as set\u2212uid root.<\/p>\n

AVAILABILITY <\/a> <\/h2>\n

clockdiff<\/b> is part of iputils<\/i> package.<\/p>\n

\n","protected":false},"excerpt":{"rendered":"

clockdiff \u2212 measure clock difference between hosts <\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[5,52,855,4],"class_list":["post-3750","post","type-post","status-publish","format-standard","hentry","category-8-administracion-del-sistema","tag-5","tag-administracion","tag-clockdiff","tag-man8"],"gutentor_comment":0,"_links":{"self":[{"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/posts\/3750","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/comments?post=3750"}],"version-history":[{"count":0,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/posts\/3750\/revisions"}],"wp:attachment":[{"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/media?parent=3750"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/categories?post=3750"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/tags?post=3750"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}