Limiting the Number of Peers
Problem
You want to limit the number of NTP peers the router will accept.
Solution
Use the ntp max-associations configuration command to limit the number of NTP associations the router will accept:
Router#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)#ntp max-associations 30
Router(config)#end
Router#
Discussion
To prevent oversubscribing valuable router resources by NTP associations, Cisco provides the ability to limit the number of associations that a router will accept. While the ntp max-associations command limits the number of inbound NTP associations, it does so without prejudice. The first 30 NTP associations, using the example above, will be permitted regardless of whom they are.
Other methods of controlling NTP associations mentioned in this chapter provide greater control and granularity than just limiting the number.