PBR and NTP(CCNP)

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PBR

- applied on ingress interface

- local generated packets wont follow PBR by default.

to process locally generated packets by PBR

#ip local policy route-map name (global configuration)

- We can mark TOS bits

# set ip predence

# set ip TOS

we can change router to 1st look into routing table and then PBR

in route-map:

#set default ip next hop

default here means look into routing table first

NTP

- source and destination port is 123

NTPv3

- only works with IPv4

NTPv4

- authentication

- works with ipv6 as well as IPv4

-NTP is client/server protocol

- NTP client polls the server for time info

Stratum level: how authoritative is the source

eg:

stratum 1: device is directly connected to atomic clock

stratum 2: devices is 1 hop away from stratum 1 device

default: stratum 8

modes of operations:

1) server mode

2) client mode

3) NTP Peers: 2 or more NTP servers are exchanging info

4) NTP broadcast/multicast: unidirectional push from NTP server. NTP server is sending info to clients by himself. client is listening passively, but we have to tell client about NTP broadcast option

NTP server and client config:

step 1)set clock time:

R2#clock set 07:47:47 31 mar 2016

step 2) make device as master and define stratum level(default is 8)

R2(config)#ntp master 1

client side:

step 1) set NTP server at client side:

R4(config)#ntp server 10.0.234.2

NTP server and client config(using NTP push feature):

server side:

R2#clock set 07:47:47 31 mar 2016

R2(config)#ntp master 1

R2(config-if)#ntp broadcast

client side:

R4(config-if)#ntp broadcast client

verify on client side:

R4#show ntp status

Clock is synchronized, stratum 2, reference is 10.0.234.2

nominal freq is 250.0000 Hz, actual freq is 249.9999 Hz, precision is 2**24

reference time is DAA75932.676CBE52 (08:07:14.404 UTC Thu Mar 31 2016)

clock offset is 14.3249 msec, root delay is 24.29 msec

root dispersion is 401.54 msec, peer dispersion is 387.19 msec

R4#

R4#

R4#

R4#show ntp ass

R4#show ntp associations

address ref clock st when poll reach delay offset disp

* 10.0.234.2 .LOCL. 1 22 64 376 24.3 -2.78 138.7 >> 10.234.2 is NTP master

* master (synced), # master (unsynced), + selected, - candidate, ~ configured

R4#

NTP authentication:

master side:

R2(config)#ntp authentication-key 1 md5 XYZ

R2(config)#ntp trusted-key 1

R2(config)#ntp authenticate

client side:

R4(config)#ntp authentication-key 1 md5 MANOJ

R4(config)#ntp trusted-key 1

R4(config)#ntp authenticate

R4(config)#ntp server 10.0.234.2 key 1