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NTP servers

Posted on 2009-05-05
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where's the best place to find reliable NTP servers to use? I am on the east coast for what its worth

Thank you
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Question by:dissolved
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akalbfell earned 500 total points
ID: 24304407
you can try to google free ntp servers and a bunch come up, best bet is anything operated by a college or the govt/military...i use these, am also on east coast and they work fine....cant remember who owns/operates them

ntp server 64.90.182.55
ntp server 18.26.4.105
ntp server 209.51.161.238
ntp server 129.6.15.28

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by:akalbfell
ID: 24304461
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by:dissolved
ID: 24304857
thanks!
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by:dissolved
ID: 24307674
if I configure an external NTP server on a router or firewall, do I need to open up udp 123?  if its a stateful firewall, shouldn't it allow the traffic back in?
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by:akalbfell
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no you shouldnt have to unless you are specifically blocking the NTP port (udp 123)
you are establishing the connection from the device so you should be fine.
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by:dissolved
ID: 24307838
ok, i added those ntp servers you had and this is what I have. is this normal? Is it synched?
Central_FL_Gas#sh ntp stat

Clock is unsynchronized, stratum 16, no reference clock

nominal freq is 250.0000 Hz, actual freq is 249.9984 Hz, precision is 2**18

reference time is CD5AD3D9.60F6E8AE (22:42:33.378 UTC Thu Mar 5 2009)

clock offset is 3.8501 msec, root delay is 152.95 msec

root dispersion is 7.86 msec, peer dispersion is 0.46 msec

Central_FL_Gas#sh ntp assoc
 

      address         ref clock     st  when  poll reach  delay  offset    disp

 ~64.90.182.55     0.0.0.0          16     -    64    0     0.0    0.00  16000.

 ~18.26.4.105      0.0.0.0          16     -    64    0     0.0    0.00  16000.

 ~209.51.161.238   0.0.0.0          16     -    64    0     0.0    0.00  16000.

 ~129.6.15.28      0.0.0.0          16     -    64    0     0.0    0.00  16000.

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

Central_FL_Gas#

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by:akalbfell
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no thats not right at all, thats not connecting to any of the NTP servers...below is what it should look like
is this an edge router or located behind other devices?




show ntp ass
 

      address         ref clock     st  when  poll reach  delay  offset    disp

+~64.90.182.55     .ACTS.            1   697  1024  377     3.0    6.16     2.8

+~18.26.4.105      .CDMA.            1   755  1024  377     8.1   -0.07     0.5

*~209.51.161.238   .CDMA.            1   710  1024  377     7.7    3.23     0.7

 ~129.6.15.28      .ACTS.            1   110  1024  377   111.7   46.91    13.6

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

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by:dissolved
ID: 24308459
its a remote site, which connects to us via MPLS. Its internet traffic goes out our (headquarters) firewall and router
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by:akalbfell
ID: 24308622
can you ping the 64.90.182.55 address from the router?
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by:dissolved
ID: 24308645
no
I do have a router (facing the internet) that does have access to an external NTP server. Should I point my routers to that?
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by:akalbfell
ID: 24308738
yeh what you can do is setup the other router to get the time and then use that as a server for the back one...pretty much what i do so the wan router is a stratum 2 ntp server

just add the ntp master 1 command to the wan router...the 1 is how many stratums away from 0 so assuming that router connections to a stratum 0 router your wan router is in stratum 1
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