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New Member

NTP client not synchronizing

I have a Red Hat 8.0 Linux NTP server that is synchronizing successfully with an Internet NTP server. I want all my Cisco devices to receive NTP updates from the Linux server. When the Red Hat server sends a NTP packet, it does not send a valid reference clock in the packet. My Cisco routers can receive updates from the same Internet NTP server where my linux box receives updates. There is not a firewall between the Linux box and my routers and udp port 123 is open between the linux box and all the routers. I have other sntp clients (windows machines) that will update from my linux box. Does anyone have an idea why the linux box would not send a valid ref clock in an NTP packet to Cisco gear?

Thanks,

RJ

3 REPLIES
Silver

Re: NTP client not synchronizing

Hmm... Can you post your ntp.config? I'm synchronizing my routers off of NTP on a Linux box. Is the Linux box a "server" or a "peer" to the router?

BTW... Cisco supports SNTP also on some routers.

New Member

Re: NTP client not synchronizing

I have attached my ntp.conf. BTW, the sntp client will not synchronize with the linux box either.

Thanks,

RJ

# Prohibit general access to this service.

restrict default ignore

# Permit all access over the loopback interface. This could

# be tightened as well, but to do so would effect some of

# the administrative functions.

restrict 127.0.0.1

# -- CLIENT NETWORK -------

# Permit systems on this network to synchronize with this

# time service. Do not permit those systems to modify the

# configuration of this service. Also, do not use those

# systems as peers for synchronization.

# --- OUR TIMESERVERS -----

# or remove the default restrict line

# Permit time synchronization with our time source, but do not

# permit the source to query or modify the service on this system.

# restrict mytrustedtimeserverip mask 255.255.255.255 nomodify notrap # noquery

# server mytrustedtimeserverip

# --- NTP MULTICASTCLIENT ---

#multicastclient # listen on default 224.0.1.1

# restrict 224.0.1.1 mask 255.255.255.255 notrust nomodify notrap

# restrict 192.168.1.0 mask 255.255.255.0 notrust nomodify notrap

# --- GENERAL CONFIGURATION ---

#

# Undisciplined Local Clock. This is a fake driver intended for backup

# and when no outside source of synchronized time is available. The

# default stratum is usually 3, but in this case we elect to use stratum

# 0. Since the server line does not have the prefer keyword, this driver

# is never used for synchronization, unless no other other

# synchronization source is available. In case the local host is

# controlled by some external source, such as an external oscillator or

# another protocol, the prefer keyword would cause the local host to

# disregard all other synchronization sources, unless the kernel

# modifications are in use and declare an unsynchronized condition.

#

server time.nist.gov

# fudge 127.127.1.0 stratum 10

#

# Drift file. Put this in a directory which the daemon can write to.

# No symbolic links allowed, either, since the daemon updates the file

# by creating a temporary in the same directory and then rename()'ing

# it to the file.

#

driftfile /etc/ntp/drift

broadcastdelay 0.008

#

# Authentication delay. If you use, or plan to use someday, the

# authentication facility you should make the programs in the auth_stuff

# directory and figure out what this number should be on your machine.

#

# authenticate yes

#

# Keys file. If you want to diddle your server at run time, make a

# keys file (mode 600 for sure) and define the key number to be

# used for making requests.

#

# PLEASE DO NOT USE THE DEFAULT VALUES HERE. Pick your own, or remote

# systems might be able to reset your clock at will. Note also that

# ntpd is started with a -A flag, disabling authentication, that

# will have to be removed as well.

#

# keys /etc/ntp/keys

New Member

Re: NTP client not synchronizing

What flavor and version of Linux are you using?

Thanks,

RJ

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