We have a 'bot with a Linux host running on an internal network connected only to a Win7 host. The Win7 host has internet access, but the Linux host does not. (historical reasons)

When I load NTPD from Meinberg on the win7 box it syncs with network servers just fine, (w32 time service is disabled). But the Linux client can't sync with that win7 server. My desktop Linux which syncs with the Internet also can't sync with that win7 server.

**trying from Linux to Windows**
root@os-linux:~# ntpdate -dvu
15 Dec 14:30:13 ntpdate[2124]: ntpdate 4.2.6p5@1.2349-o Fri Oct 23 16:45:28 UTC 2015 (1)
Looking for host and service ntp
host found : robot-10424.ith.local
transmit( Server dropped: no data
server, port 123
stratum 0, precision 0, leap 00, trust 000
refid [], delay 0.00000, dispersion 64.00000
transmitted 4, in filter 4
reference time:    00000000.00000000  Sun, Dec 31 1899 16:00:00.000
originate timestamp: 00000000.00000000  Sun, Dec 31 1899 16:00:00.000
transmit timestamp:  da1b12fb.91411c7f  Tue, Dec 15 2015 14:30:19.567
filter delay:  0.00000  0.00000  0.00000  0.00000 
         0.00000  0.00000  0.00000  0.00000 
filter offset: 0.000000 0.000000 0.000000 0.000000
         0.000000 0.000000 0.000000 0.000000
delay 0.00000, dispersion 64.00000
offset 0.000000
15 Dec 14:30:21 ntpdate[2124]: no server suitable for synchronization found

heres the win7 (NTPD server) conf contents....

# /etc/ntp.conf, configuration for ntpd; see ntp.conf(5) for help

driftfile /var/lib/ntp/ntp.drift

# Enable this if you want statistics to be logged.
#statsdir /var/log/ntpstats/

statistics loopstats peerstats clockstats
filegen loopstats file loopstats type day enable
filegen peerstats file peerstats type day enable
filegen clockstats file clockstats type day enable

# Specify one or more NTP servers.

# Use servers from the NTP Pool Project. Approved by Ubuntu Technical Board
# on 2011-02-08 (LP: #104525). See http://www.pool.ntp.org/join.html for
# more information.
#server 0.ubuntu.pool.ntp.org
#server 1.ubuntu.pool.ntp.org
#server 2.ubuntu.pool.ntp.org
#server 3.ubuntu.pool.ntp.org
# Use Ubuntu's ntp server as a fallback.
server ntp.ubuntu.com

# 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 noquery
restrict -6 default kod notrap nomodify nopeer noquery

# Local users may interrogate the ntp server more closely.
restrict ::1

# Clients from this (example!) subnet have unlimited access, but only if
# cryptographically authenticated.
#restrict mask notrust

# If you want to provide time to your local subnet, change the next line.
# (Again, the address is an example only.)

# 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

win7 ntp.conf

# NTP Network Time Protocol 
# **** ATTENTION ****: *You have to restart the NTP service when you change this file to activate the changes* 
# Configuration File created by Windows Binary Distribution Installer Rev.: 1.27  mbg
# please check http://www.ntp.org for additional documentation and background information
# restrict access to avoid abuse of NTP for traffic amplification attacks 
# see http://news.meinberg.de/244 for details  
#restrict default noquery nopeer nomodify notrap  
#restrict -6 default noquery nopeer nomodify notrap  

# allow status queries and everything else from localhost 
restrict -6 ::1 

# if you need to allow access from a remote host, you can add lines like this: 
restrict mask 

# Use drift file 
driftfile "c:\Program Files\NTP\etc\ntp.drift"

# your local system clock, could be used as a backup
# (this is only useful if you need to distribute time no matter how good or bad it is)
# but it should operate at a high stratum level to let the clients know and force them to
# use any other timesource they may have.
#fudge stratum 12

# Use a NTP server from the ntp pool project (see http://www.pool.ntp.org)
# Please note that you need at least four different servers to be at least protected against
# one falseticker. If you only rely on internet time, it is highly recommended to add
# additional servers here. 
# The 'iburst' keyword speeds up initial synchronization, please check the documentation for more details!
 server 0.pool.ntp.org iburst minpoll 6 maxpoll 7
 server 1.pool.ntp.org iburst minpoll 6 maxpoll 7
 server 2.pool.ntp.org iburst minpoll 6 maxpoll 7
 server 3.pool.ntp.org iburst minpoll 6 maxpoll 7
 server 4.pool.ntp.org iburst minpoll 6 maxpoll 7

# Use specific NTP servers
server 3.north-america.pool.ntp.org iburst minpoll 6 maxpoll 7
  • 1
    Is the Windows Firewall turned on, on the Win7 machine? If so, you need to poke a hole for UDP 123 in. – Ryan Ries Dec 15 '15 at 23:54

Thanks Ryan, ntpd had to be added to the list in windows firewall. Obvious in hindsight, but not to windows newbie I guess.

  • Don't forget to come back in a couple days and mark your answer as accepted. :) – Ryan Ries Dec 16 '15 at 21:26

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