[ntp:questions] Windows Time with NTPv4

Ryan Malayter malayter at gmail.com
Thu Mar 13 13:55:42 UTC 2008

On Mar 13, 3:56 am, Martin Burnicki <martin.burni... at meinberg.de>
> The default was that ntpd just dropped those requests, i.e. didn't send a
> response at all, in which case the w32time clients were unable to
> synchronize to the NTP server, unless they were reconfigured correctly to
> send "client" requests.

Hmm... I've notice lots of Windows machines that connect to my pool
server, which runs ntpd 4.2.4p4 at 1.520-modena (Meinberg). Wireshark
indicates that the ntp srever does reply with Symmetric Active packets
to thse Windows clients (mode 1), even though no peers or
authentication are configured. I even have a "restrict default nopeer"
in there.

(I say "Windows clients" as I am guessing anything that is NTPv3,
clock precision of -6, and requests symmetric active is a Windows

I've also never had any trouble syncing to any pool.ntp.org servers
using w32time, even without the 0x8 client mode identifier.

My pool ntp.conf:
# Use specific NTP servers
server ntpmaster1.sys.cogentco.com iburst
server ntpmaster2.sys.cogentco.com
server ntp-2.cso.uiuc.edu
server ntp3.cs.wisc.edu

#Local network Peers
peer ntp1.bai.org
peer ntp2.bai.org

restrict default kod nomodify notrap nopeer
restrict <localsubnet> mask nomodify notrap
restrict <localsubnet> mask nomodify notrap

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