I have two debian wheezy machines on the same LAN that have clocks synchronized using NTP. Using date I see that the times are synchronized. I then set the time back about 30 seconds using date --set on one of the machines.When will the ntp service correct the clock? It's been about 15 minutes and the two machines still have a 30 second difference in the output of date. I know I can force a clock update, but I want to know how quickly the ntp service will update the clock automatically.Here`s some status:root@unassigned-hostname:# ntpq -p     remote           refid      st t when poll reach   delay   offset  jitter============================================================================== materialinmotio .CDMA.           1 u  621 1024  377   78.039  18621.9 18622.5 hadb2.smatwebde 200.98.196.212   2 u  451 1024  377   36.824  18621.8 18622.1 ntp.newfxlabs.c 216.218.192.202  2 u   25 1024  377   69.693  18623.6 17241.1 time.tritn.com  216.218.192.202  2 u  284 1024  377   69.584    0.466 7038.56root@unassigned-hostname:# service ntp statusNTP server is running.and my /etc/ntp.conf:# /etc/ntp.conf, configuration for ntpd; see ntp.conf(5) for helpdriftfile /var/lib/ntp/ntp.drift# Enable this if you want statistics to be logged.#statsdir /var/log/ntpstats/statistics loopstats peerstats clockstatsfilegen loopstats file loopstats type day enablefilegen peerstats file peerstats type day enablefilegen clockstats file clockstats type day enable# You do need to talk to an NTP server or two (or three).#server ntp.your-provider.example# pool.ntp.org maps to about 1000 low-stratum NTP servers.  Your server will# pick a different set every time it starts up.  Please consider joining the# pool: <http://www.pool.ntp.org/join.html>server 0.debian.pool.ntp.org iburstserver 1.debian.pool.ntp.org iburstserver 2.debian.pool.ntp.org iburstserver 3.debian.pool.ntp.org iburst# Access control configuration; see /usr/share/doc/ntp-doc/html/accopt.html for# details.  The web page <http://support.ntp.org/bin/view/Support/AccessRestrictions># might also be helpful.## Note that restrict applies to both servers and clients, so a configuration# that might be intended to block requests from certain clients could also end# up blocking replies from your own upstream servers.# By default, exchange time with everybody, but don't allow configuration.restrict -4 default kod notrap nomodify nopeer noqueryrestrict -6 default kod notrap nomodify nopeer noquery# Local users may interrogate the ntp server more closely.restrict 127.0.0.1restrict ::1# Clients from this (example!) subnet have unlimited access, but only if# cryptographically authenticated.#restrict 192.168.123.0 mask 255.255.255.0 notrust# If you want to provide time to your local subnet, change the next line.# (Again, the address is an example only.)#broadcast 192.168.123.255# If you want to listen to time broadcasts on your local subnet, de-comment the# next lines.  Please do this only if you trust everybody on the network!#disable auth#broadcastclient
When will ntp update the time
debian;ntp;ntpd