access-control vlan

Enables the VLAN containment for Network Time Protocol (NTP).
Syntax
access-control vlan vlan-id
no access-control vlan vlan-id
Command Default

VLAN containment for NTP is not enabled.

Parameters
vlan-id
Specifies the VLAN ID number.
Modes

NTP configuration mode

Usage Guidelines

The management interface is not part of any VLAN. When configuring the VLAN containment for NTP, the management interface is not used to send or receive the NTP packets.

When VLAN is configured,

  • NTP time servers should be reachable through the interfaces that belong to the configured VLAN. Otherwise, NTP packets are not transmitted. NTP packets are not trasmitted in the case of both the unicast and the broadcast server/client if the servers are not reachable through the interfaces that belong to the configured VLAN.
  • NTP broadcast packets are sent only on the interface that belongs to the configured VLAN.
  • The received unicast or broadcast NTP packets are dropped if the interface on which the packets have been received does not belong to the configured VLAN.

The no form of the command removes the specified VLAN containment for NTP.

Examples

The following example enables VLAN containment for NTP. 

device(config)# ntp
device(config-ntp)# access-control vlan 100
Parent topic: Commands A and B