I have a Cisco 877W which I'm using for my home ADSL connection (and as a refresher in Cisco IOS). I've got a working config in-place with my PPPoA connection coming online correctly, and VLANs and other settings configured as I want them, but I can't crack the NTP configuration.

For NTP, I have the following defined

ntp server 0.uk.pool.ntp.org source Dialer0
ntp server 1.uk.pool.ntp.org source Dialer0
ntp server 2.uk.pool.ntp.org source Dialer0
ntp server 3.uk.pool.ntp.org source Dialer0

This setup works fine when issued in Global Configuration Mode when the Dialer0 interface (ATM0.1) is up. The configuration fails at startup though:

Translating "1.uk.pool.ntp.org"...domain server (208.67.222.222) (208.67.220.220)

ntp server 1.uk.pool.ntp.org source Dialer0
                                            ^
% Invalid input detected at "^" marker.

This is repeated for the other servers defined.

Obviously the DNS lookup for the server(s) fails because the DNS servers cannot be accessed because the external interface is not yet online.

Is there a way to delay the NTP configuration until afte the Dialer0 interface is fully initialised? Can the NTP commands be triggered by the Line Protocol on the Dialer0 interface transitioning to the up state? Alternatively, can the NTP commands be delayed for 5 minutes after the router has finished initialising?

Any advice, or pointers to useful documentation or examples gratefully received ...