NTP on Loopback Interface

[bob.bartlett]

I am trying to enable NTP as the source for the loopback interface and when I set the command "ntp source Loopback0" the router says the following:

Router(config)#ntp source Loopback0
ntpio_set_global_source failed
Router(config)#
Jan 27 21:19:24.471 UTC: ntpio_set_global_source: not an NTP interface.

Any ideas on why this can't be done.

[Leo Laohoo · Accepted solution]

What is the version of your IOS?

Try the following command:  ntp server A.B.C.D source loop0 {prefer}