NTP question

mkoopsen · ‎05-14-2003

Can somebody tell me if all the NTP packets are blocked on an interface if you put the command "ntp disable" on an interface or are the NTP request from hosts behind that interface ignored?

The documentation is not very clear about this.

http://www.cisco.com/en/US/products/sw/iosswrel/ps1831/products_configuration_guide_chapter09186a00800ca66f.html#1001288

Thanks,

Martijn

aghaznavi · ‎05-20-2003

Hello,

If "ntp disable" is configured on a router interface, NTP packets will be ignored coming into the router through that interface. Packets will be blocked only if it is denied through an access list or something like that. In the "ntp-disable" case, the NTP service on the router will be disabled and therefore the UDP packets that carry NTP information will have no place to go in the router and hence will be discarded as "UDP unknown port" or some other similer error. I am not sure if the router will send an ICMP back to the source?