...
restrict default notrust nomodify noquery
restrict 127.0.0.1
restrict 146.6.177.21
restrict 128.83.185.40
restrict 128.83.185.41
restrict 146.6.177.23
restrict 146.6.177.22
restrict 146.6.177.15
restrict 146.6.177.16
restrict 172.16.54.150
restrict 128.83.59.200
Note: The IP addresses listed in the configuration file example are the devices allowed to access NTP service. Additional examples could be needed.
Access Control Lists (ACLs)
A request to ITS-Networking can also be sent to create an ACL rule at the router level to restrict NTP to a specific device
Example:
Device IP: 129.116.109.34
Device MAC: 5cf3.fc27.9ba4
Device VLAN: 350
ACL Example:
no ip access-list extended UTL_block_telepresence_ntp
ip access-list extended UTL_block_telepresence_ntp
remark deny all NTP except for UT NTP servers
permit udp host 128.83.185.40 host 129.116.109.34 eq ntp
permit udp host 128.83.185.41 host 129.116.109.34 eq ntp
deny udp any host 129.116.109.34 eq ntp
remark allow everything else
permit ip any any
interface vlan 350
ip access-group UTL_block_telepresence_ntp out