Cisco IOS:
!
clock timezone MSK 4
!
access-list 10 remark NTP Servers ACL
access-list 10 permit host 80.240.109.1
access-list 10 permit host 80.240.109.22
access-list 10 permit host 194.87.0.22
access-list 10 permit host 194.87.0.28
access-list 10 permit host 195.2.64.5
access-list 10 permit host 195.2.64.6
access-list 10 permit host 213.59.0.3
access-list 10 permit host 62.117.76.138
access-list 10 permit host 62.117.76.141
access-list 10 permit host 62.117.76.142
access-list 10 deny any
!
access-list 20 remark NTP Clients ACL
access-list 20 deny any
!
ntp clock-period 17179876
ntp update-calendar
ntp access-group peer 10
ntp access-group serve-only 20
ntp server 80.240.109.1
ntp server 80.240.109.22
ntp server 194.87.0.22
ntp server 194.87.0.28
ntp server 195.2.64.5 prefer
ntp server 195.2.64.6
ntp server 213.59.0.3
ntp server 62.117.76.138
ntp server 62.117.76.141
ntp server 62.117.76.142
ntp master 10
!
Cisco ASA:
!
clock timezone MSK 4
!
ntp server 80.240.109.1
ntp server 80.240.109.22
ntp server 194.87.0.22
ntp server 194.87.0.28
ntp server 195.2.64.5 prefer
ntp server 195.2.64.6
ntp server 213.59.0.3
ntp server 62.117.76.138
ntp server 62.117.76.141
ntp server 62.117.76.142
!