[c-nsp] 15.1(2)SY3 not NTP syncing

[Phil Mayers]

All,

We've just replaced a sup720 (killed by flood damage) and brought the 
new box up on the above IOS version, and it's not NTP syncing. The 
config is a straight restore from a box running 15.1(1)SY1

It's been over an hour now, no success syncing...

The odd thing is that this specific physical box had (2)SY3 on it in our 
spares rack before being repurposed and was NTP-synced fine, using our 
standard templated config.

The "debug ntp" output is unhelpful except to confirm it's sending and 
receiving NTP messages, but apparently not doing anything with them:

NTP message sent to x.x.y.y, from interface 'NULL' (0.0.0.0).
NTP message received from x.x.5.12 on interface 'Vlan3846' (x.x.x.x).
NTP Core(DEBUG): ntp_receive: message received
NTP Core(DEBUG): ntp_receive: peer is 0x00000000, next action is 4.

The peers report huge dispersion:

   address  ref clock       st   when   poll reach  delay  offset   disp
  ~x.x.x.x  .INIT.          16      -   1024     0  0.000   0.000 15937.

...despite the hardware clock being about a second out of real/NTP time. 
Under detail the associations are claimed "insane":

x.x.x.x configured, ipv4, insane, invalid, unsynced, stratum 16
ref ID .INIT., time 00000000.00000000 (00:00:00.000 GMT Mon Jan 1 1900)
our mode client, peer mode unspec, our poll intvl 64, peer poll intvl 1024
root delay 0.00 msec, root disp 0.00, reach 0, sync dist 15938.02
delay 0.00 msec, offset 0.0000 msec, dispersion 15937.50, jitter 0.00 msec
precision 2**21, version 4
assoc id 53838, assoc name x.x.x.x
assoc in packets 0, assoc out packets 6, assoc error packets 0
org time D8394B1D.78CEFC6B (11:57:17.471 GMT Mon Dec 15 2014)
rec time 00000000.00000000 (00:00:00.000 GMT Mon Jan 1 1900)
xmt time 00000000.00000000 (00:00:00.000 GMT Mon Jan 1 1900)
filtdelay =     0.00    0.00    0.00    0.00    0.00    0.00    0.00    0.00
filtoffset =    0.00    0.00    0.00    0.00    0.00    0.00    0.00    0.00
filterror =  16000.0 16000.0 16000.0 16000.0 16000.0 16000.0 16000.0 16000.0
minpoll = 6, maxpoll = 10

Aside from reloading the box, any ideas? I've tried removing the NTP 
ACLs to no avail...

Cheers,
Phil