router not synchronizing with ntp server

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Mar 21st, 2007
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My router is not synchronizing with my ntp server , giving here the details,for ntp staus command and ntp assosciation..

!

scheduler allocate 20000 1000

ntp source FastEthernet0/0

ntp master 2

ntp server 172.17.7.1


#sh ntp status

Clock is synchronized, stratum 2, reference is 127.127.7.1

nominal freq is 250.0000 Hz, actual freq is 250.0000 Hz, precision is 2**18

reference time is C1E75CDC.B692885E (14:31:16.713 INDIA Sun Feb 2 2003)

clock offset is 0.0000 msec, root delay is 0.00 msec

root dispersion is 8656633.33 msec, peer dispersion is 8656633.33 msec

#sh ntp associations


address ref clock st when poll reach delay offset disp

*~127.127.7.1 .LOCL. 1 12 64 377 0.0 0.00 0.0

+~172.17.7.1 .LCL. 1 4 64 377 26.3 130362 5.3

* master (synced), # master (unsynced), + selected, - candidate, ~ configured



I dont understand what is that 127.127.7.1 ,

my ntp server configured in router is 172.17.7.1 but i think it is not synchronizing with that, can anybody help me out...in resolving this issue..

thanks in advance...


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Joe Clarke Wed, 03/21/2007 - 23:34
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127.127.7.1 indicates that this router is an authoritative NTP source, and its clock is synchronized with itself. I'm not sure you want to configure this router as a master. If you just want it to be an NTP client of 172.17.7.1, then remove the ntp master command, and the clock should sync.


If you do want this device to be an authoritative time source, configure yourself with a stratum of 3 or higher:


ntp master 3

rajesh_colt Thu, 03/22/2007 - 01:12
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hi,


i removed ntp master command...then also it is not getting synchronized with ntp server..giving the details..below ..please help thanks in advance...

#sh ntp associations


address ref clock st when poll reach delay offset disp

~172.17.7.1 0.0.0.0 16 - 64 0 0.0 0.00 16000.

* master (synced), # master (unsynced), + selected, - candidate, ~ configured


Joe Clarke Thu, 03/22/2007 - 07:28
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Check to make sure that there is no firewall or filter between you and your NTP server. NTP operates over UDP port 123. You might also want to enable debug ntp packets to see if the NTP server is replying to your sync requests.

garethcoco Thu, 03/22/2007 - 07:31
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Also try setting the time manually to approximately the correct time. Sometimes if the time on the router and the NTP server are too far apart the device will not sync.

rajesh_colt Thu, 03/22/2007 - 08:01
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can you give me sample ntp configuration on ntp server and on ntp client...

both ntp server and ntp clients are cisco routers. ntp server router is 3600 series router and it is getting synchronized with another ntp server , it is working also. but the other router 2600 series which is connected through serial interface to 3600 series is not getting synchronized...

Joe Clarke Thu, 03/22/2007 - 08:35
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For a client, I just typically add:


clock timezone EST -5

clock summer-time EDT recurring

ntp server x.x.x.x


As for the server, you can set the device's local clock to be authoritative using the ntp master command. You can optionally configure NTP broadcasts on various interfaces using the ntp broadcast command.


More info plus some configuration examples are available at http://www.cisco.com/en/US/products/sw/iosswrel/ps1831/products_configuration_guide_chapter09186a00800ca66f.html#wp1001170 .

rajesh_colt Thu, 03/22/2007 - 23:53
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In client I configured ntp broadcast client on my serial interface , which is directly connecting to my ntp master..and in ntp

master serial interface ntp broadcast X.X.X.X (client address) , my client gets the ntp broadcast also, but still it is not getting synchronizing


in ntp client router my config is


ntp clock-period 17179871

ntp source Multilink1



in ntp server router(172.26.X.X) config (from where my client router needs to get synchronize)


ntp clock-period 17179871

ntp source FastEthernet0/0 (interface gets connected to 172.17.x.x)

ntp master 2

ntp server 172.17.x.x (this is the parent ntp server from where my ntp server router get synchronization )







I am attaching sh ntp associations, sh ntp associations detail, sh ntp status in my router (client router)


is their any thing mor i need to configure in my client router and parent router.... pls help thanks in advance...


#sh ntp associations


address ref clock st when poll reach delay offset disp

192.168.100.5 172.17.7.1 2 43 64 76 2.2 48034. 875.2

* master (synced), # master (unsynced), + selected, - candidate, ~ configured



#sh ntp associations detail

192.168.100.5 dynamic, insane, invalid, stratum 2

ref ID 172.17.7.1, time C9ADEBCE.AEB67D4D (11:31:50.682 india Fri Mar 23 2007)

our mode bdcast client, peer mode bdcast, our poll intvl 64, peer poll intvl 64

root delay 42.21 msec, root disp 3292.74, reach 37, sync dist 4190.201

delay 2.24 msec, offset 48034.3069 msec, dispersion 875.24

precision 2**18, version 3

org time C9ADECE0.A3D1E395 (11:36:24.639 india Fri Mar 23 2007)

rcv time C9ADECB0.9AB2A301 (11:35:36.604 india Fri Mar 23 2007)

xmt time C9ADEC85.92DF1C1E (11:34:53.573 india Fri Mar 23 2007)

filtdelay = 2.37 2.24 2.35 2.67 4.38 0.00 0.00 0.00

filtoffset = 48034.5 48034.3 48034.2 48033.9 48035.0 0.00 0.00 0.00

filterror = 0.02 0.03 0.05 0.06 0.08 16000.0 16000.0 16000.0



#sh ntp status

Clock is unsynchronized, stratum 16, no reference clock

nominal freq is 250.0000 Hz, actual freq is 249.9999 Hz, precision is 2**24

reference time is C9ADE8CD.92D79FE1 (11:19:01.573 india Fri Mar 23 2007)

clock offset is 0.0000 msec, root delay is 0.00 msec

root dispersion is 0.02 msec, peer dispersion is 0.02 msec




Joe Clarke Fri, 03/23/2007 - 09:35
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Since you want to use broadcast NTP, you need to configure the interface on which to send the updates to the client (i.e. using the ntp broadcast command). And on the client, you need to enable reception of broadcast. So, say that the server is connected to the client across interface Multilink1. Do this on the server:


interface Multiink1

ntp broadcast


Then on the client:


interface Multilink1

ntp broadcast client

rajesh_colt Fri, 03/23/2007 - 23:31
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I have already configured it in the interface before the above post , it is getting ntp packets ...as you can see in the details sh ntp associations, sh ntp associations detail, sh ntp status..for your refernce i am attachin it agian...


#sh ntp associations


address ref clock st when poll reach delay offset disp

192.168.100.5 172.17.7.1 2 43 64 76 2.2 48034. 875.2

* master (synced), # master (unsynced), + selected, - candidate, ~ configured



#sh ntp associations detail


192.168.100.5 dynamic, insane, invalid, stratum 2

ref ID 172.17.7.1, time C9ADEBCE.AEB67D4D (11:31:50.682 india Fri Mar 23 2007)

our mode bdcast client, peer mode bdcast, our poll intvl 64, peer poll intvl 64

root delay 42.21 msec, root disp 3292.74, reach 37, sync dist 4190.201

delay 2.24 msec, offset 48034.3069 msec, dispersion 875.24

precision 2**18, version 3

org time C9ADECE0.A3D1E395 (11:36:24.639 india Fri Mar 23 2007)

rcv time C9ADECB0.9AB2A301 (11:35:36.604 india Fri Mar 23 2007)

xmt time C9ADEC85.92DF1C1E (11:34:53.573 india Fri Mar 23 2007)

filtdelay = 2.37 2.24 2.35 2.67 4.38 0.00 0.00 0.00

filtoffset = 48034.5 48034.3 48034.2 48033.9 48035.0 0.00 0.00 0.00

filterror = 0.02 0.03 0.05 0.06 0.08 16000.0 16000.0 16000.0



#sh ntp status


Clock is unsynchronized, stratum 16, no reference clock

nominal freq is 250.0000 Hz, actual freq is 249.9999 Hz, precision is 2**24

reference time is C9ADE8CD.92D79FE1 (11:19:01.573 india Fri Mar 23 2007)

clock offset is 0.0000 msec, root delay is 0.00 msec

root dispersion is 0.02 msec, peer dispersion



in sh ntp status 192.168.100.5 is my ntp broadcast multilink interface and 172.17.7.1 is where ntp broadcast router synchronize with...and theese are all taken from ntp broadcast client router..so it clearly says that it recives the packet but not synchronizing....


great thanks for your help and support...and hope to continue

Joe Clarke Sat, 03/24/2007 - 09:35
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It would be helpful to see the whole picture including a show ver and show run from both routers. The output of show ntp status and show ntp associations from the server router would also help.

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