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Community Member

IMplementing NTP :Network time protocol


I have one 3640 , 2610 , 2924 devices in my LAN .

these devices are not having system clock calender.

I configured my PC (windows 2000 professional) as providng Time service

in LAN. I am not syncing over WAN ,,it is inside my LAN.

I have used just one command in 3640 router after configuring my PC as Time server ,,,

command is as follows .....


Ntp server prefer

! is my PC ip address and is 3640 router's ethernet ip address.

these are connected through Switch 2924

THough i am synchronizing my PC time through internet time servers , but i have enabled w32time service of windows 2000 Pro. and configred it as local time server for my LAN by editing registry keys.

i have not used any other command except ntp server prefer.

Also my router time is in skew of server.

my cisco ios version details ----

Cisco Internetwork Operating System Software

IOS (tm) 3600 Software (C3640-IS40-M), Version 12.0(4)T, RELEASE SOFTWARE (fc1)

Copyright (c) 1986-1999 by cisco Systems, Inc.

Compiled Thu 29-Apr-99 16:01 by kpma

Image text-base: 0x600088F0, data-base: 0x60B56000

ROM: System Bootstrap, Version 11.1(20)AA1, EARLY DEPLOYMENT RELEASE SOFTWARE (f


Head_Office uptime is 2 days, 3 hours, 29 minutes

System restarted by power-on at 10:29:38 ast Mon Aug 26 2002

System image file is "flash:c3640-is40-mz_120-4_T.bin"

cisco 3640 (R4700) processor (revision 0x00) with 28672K/4096K bytes of memory.

Processor board ID 14393449

R4700 CPU at 100Mhz, Implementation 33, Rev 1.0

Bridging software.

X.25 software, Version 3.0.0.

1 Ethernet/IEEE 802.3 interface(s)

5 Serial network interface(s)

DRAM configuration is 64 bits wide with parity disabled.

125K bytes of non-volatile configuration memory.

8192K bytes of processor board System flash (Read/Write)

Configuration register is 0x2102

suggest me what to do ?



Re: IMplementing NTP :Network time protocol

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Community Member

Re: IMplementing NTP :Network time protocol

You may have to configure timezone in your router as well.

Community Member

Re: IMplementing NTP :Network time protocol

I don't believe that the w32time service will act as an ntp server. I think its a client only. If you want an ntp server, start here:

.. and search for time server software. More info than you will ever want to know about ntp. I run the NT port of the standard xntpd server daemon, and it works great.

Another option is set one of your routers as an ntp server. IOS basically runs a full xntpd daemon and can function as both a client and a server. Set one of your routers to pull time from a few public stratum2 servers. Then set the other routers to pull time from that router. Set your pc to pull time from it as well.


Community Member

Re: IMplementing NTP :Network time protocol



but i have configured windows 2000 as a time server ,, by editing some Ntp registry keys ,, and other machines are synchronizing their time from 2000 time server,, then why not cisco router ?

Anyway ,, even i stopped time service from 2000 and used some downloaded time server software , then also only routers is not getting synchronized ,, but other PC's are taking time from time server.

There is one more thing in these routers ... After reload they get their default time somting like "March 1993" date & time . and we need to set the clock maually using "clock set" command.

I have configured Timezone information also.

ya ,, of course ,, we can configure one router as a MASTER clock ,, synchronizing all other devices.

i did the same , it is working fine. ,, but what if MASTER Router reloads due to some reason , then other devices looses time keeping. and after reload of master roouter we again need to set its time.

please give me some more hints

thanks n regards


Community Member

Re: IMplementing NTP :Network time protocol

If I understand your question, you're trying to get the router and internal devices to time sync its internal clock. On our networks, I sync the external gateway's clock using


ntp clock-period 17208462

ntp source Ethernet0/1

ntp access-group peer 10

ntp server

ntp server prefer

ntp server


access-list 10 permit

access-list 10 permit

access-list 10 permit

access-list 10 permit

access-list 10 permit

access-list 10 deny any log


This permits the external gateway's E0/1 to sync to an external time system, then act as an internal time source for all devices on the /24. On the servers and PCs, I set them to use SNTP to the external gateway's internal interface, E0/0


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