Using ping, tracert, and system debugging ··············································································································· 1

Ping ····················································································································································································· 1

Using a ping command to test network connectivity ···························································································· 1

Ping example ···························································································································································· 1

Tracert ················································································································································································ 3

Prerequisites ······························································································································································ 4

Using a tracert command to identify failed or all nodes in a path ····································································· 4

Tracert example ························································································································································ 4

System debugging ···························································································································································· 6

Debugging information control switches················································································································ 6

Debugging a feature module ·································································································································· 7

Configuring NTP ·························································································································································· 8

Overview ············································································································································································ 8

How NTP works ························································································································································ 8

NTP architecture ······················································································································································· 9

Association modes ················································································································································ 10

NTP security ··························································································································································· 12

NTP for MPLS VPNs ·············································································································································· 13

Protocols and standards ······································································································································· 13

Configuration restrictions and guidelines ···················································································································· 13

Configuration task list ···················································································································································· 14

Enabling the NTP service ·············································································································································· 14

Configuring NTP association modes ···························································································································· 14

Configuring NTP in client/server mode ·············································································································· 14

Configuring NTP in symmetric active/passive mode ························································································ 15

Configuring NTP in broadcast mode ·················································································································· 16

Configuring NTP in multicast mode ····················································································································· 17

Configuring access control rights ································································································································· 18

Configuring NTP authentication ··································································································································· 18

Configuring NTP authentication in client/server mode ····················································································· 18

Configuring NTP authentication in symmetric active/passive mode ······························································· 20

Configuring NTP authentication in broadcast mode ························································································· 23

Configuring NTP authentication in multicast mode ··························································································· 24

Configuring NTP optional parameters ························································································································· 27

Specifying the source interface for NTP messages ···························································································· 27

Disabling an interface from processing NTP messages ···················································································· 27

Configuring the maximum number of dynamic associations ············································································ 28

Configuring a DSCP value for NTP packets ······································································································· 28

Configuring the local clock as a reference source ····································································································· 29

Displaying and maintaining NTP ································································································································· 29

NTP client/server mode configuration example ········································································································· 29

IPv6 NTP client/server mode configuration example ································································································· 31

NTP symmetric active/passive mode configuration example ··················································································· 32

IPv6 NTP symmetric active/passive mode configuration example ··········································································· 34

NTP broadcast mode configuration example ············································································································· 36

NTP multicast mode configuration example ················································································································ 37

IPv6 NTP multicast mode configuration example ······································································································· 40

Configuration example for NTP client/server mode with authentication ································································· 43