This tutorial is all about NTP Authentication configuration on cisco router.to perform this lab i have used cisco packet tracer Lab.To ensure that erroneous time information is not propagated throughout the network, NTP authentication can be configured.
Step 1:First Design the Topology diagram and assign IP Addreses.
assign ip address on router interface and server as i have mentioned in Topology diagram.And wait till all port show green signal.
Step 2: Configure Both NTP Server with key 1 and password is redhat.
Step 3:Now configure Router D as NTP Client of Both NTP Server.
D(config)#clock timezone CST -6 D(config)#ntp server 10.0.0.1 D(config)#ntp server 10.0.0.5
STEP 4:Now configure NTP authentication on RouterD:
D(config)#ntp authentication-key 1 md5 redhat D(config)#ntp trusted-key 1 D(config)#ntp server 10.0.0.1 key 1
Note that authentication-key must be same on the both NTP Devices.
Step 5:Verify NTP to see current date and time.
D#show clock 9:25:43.712 CST Sun Oct 29 2017
Step 6:Check the status of NTP synchronization.
D#show ntp status Clock is synchronized, stratum 2, reference is 10.0.0.1 nominal freq is 250.0000 Hz, actual freq is 249.9990 Hz, precision is 2**19 reference time is DD76414A.000000D7 (15:24:58.215 UTC Sun Oct 29 2017) clock offset is 0.00 msec, root delay is 0.00 msec root dispersion is 0.02 msec, peer dispersion is 0.02 msec.