The Network Time Protocol
(NTP) is a protocol used for synchronizing the clocks of network devices over
data networks. In Cisco router sometimes
obtaining the correct time is extremely important because a variety of services
depend on it. The logging service shows each log entry with the date and time so
for the accurate data you need the updated time and date at every time.
Similarly in configuring some routing protocol’s authentication you also need
to have the updated and accurate time on the every router on which you want to
enable the authentication. You can sync your router’s time and date with NTP
server. You can use some internet NTP server or own master NTP server from
within your internal network if you have. In this gns3 lab we will learn that how we can
perform NTP configuration on Cisco router and can sync your router time with
the internet NTP server.
In this lab we have three
routers R1, R2 and R3. R1 is connected to internet.
·Configure R1 for automatically sync
its time from internet NTP sever and configure as NTP master.
·Configure R2 and R3 as NTP client and
enable them to update their time from R1.
For configuring this gns3
lab you need internet connectivity for accessing the live NTP server from your internal
GNS3 router. For providing the internet connectivity on R1 you have to add a cloud
for network nodes in gns3 then associate your physical network interface with
it, e1/0 is the interface that is connected to your physical interface (cloud)
so you must assign IP address from same subnet that your physical interface
have. Since my physical interface has IP 192.168.1.3/24 with gateway
192.168.1.1 therefore I have assign 192.168.1.11 to e1/0.
ip address 192.168.1.11 255.255.255.0
ip route 0.0.0.0 0.0.0.0
192.168.1.1 (for providing internet access)
After the above
configuration you must able to ping your gateway and any internet address.
You can find IP address of
live NTP server by pinging “pool.ntp.org”
R1(config)# Ntp server 220.127.116.11
R1(config)#ntp server master
You can verify the NTP
configuration by following commands:
R1(config)#show NTP status
R1(config)#show ntp clock
create the connectivity with R2 and R3.