IP Services: SNMP, NTP

NTP:

• NTP server: (global) ntp master 7 ß stratum 7
• NTP symmetric active mode: router/switch mutually synchronizes with another NTP host, configured with ntp peer command. (global) ntp peer 10.1.1.1
• NTP broadcast client: Listens to NTP broadcasts on the Ethernet. (int) ntp broadcast client
• NTP client: configures, “ntp server 10.1.1.1”
• Authentication on NTP:
  • ntp authentication-key 1 md5 <name>
  • ntp authenticate
  • ntp trusted-key 1
• under interface configure “ntp broadcast” (broadcast the time)
• show ntp associations

 SNMP

• SNMPv1: simple authentication with communities, used MIB-I
• SNMPv2: removed requirement for communities, added GetBulk and inform messages, MIB-II
• SNMPv2c: only difference, allowed SNMPv1 style communities with SNMPv2
• SNMPv3: better security, backward compatibility to communities.
• communities: read-only, read-write, trap.
• Inform requests are acknowledged with an SNMP response packet.
• Messages:
  • Response: responds to information in Get and Set requests.
  • Inform: A message used b/w SNMP managers to allow MIB data to be exchanged about agents they both manage.
• MIBS:
  • RMON is outside MIB-II
• SNMPv3 adds authentication and encryption. MD5 and SHA creates a message digest for each protocol message (authentication) and DES to encrypt messages providing encryption (privacy).
• SNMP embedded event manager
  • automatic recovery actions are performed without need to fully reboot the routing device
  • allows event management capability directly inside the Cisco IOS devices.
  • action snmp-trap enables the traps event-manager command, also requires snmp-server configuration.
  • two types of EEM policy: applets and script
  • E.g: event manager applet IOSWD_Sample1
    • event ioswdsysmon sub1 cpu-proc taskname “task 1” op ge val 25 period 10 (triggers an applet when avg cpu usage is greater than or equat to 25% for 10 seconds. )
    • action 1.0 syslog msg “IOSWD_Sample1 Policy Triggered” (generates syslog notification)