Version 8.3.7.0 Introduced on the S4810.
Version 7.6.1.0 Introduced on the S-Series.
Version 7.5.1.0 Introduced on the C-Series.
pre-Version 
6.1.1.0
Introduced on the E-Series.
ntp disable
Prevent an interface from receiving NTP packets.
C-Series, E-Series, S-Series, Z-Series, S4810
Syntax
ntp disable
To re-enable NTP on an interface, use the no ntp disable command.
Defaults Disabled (that is, if you configure an NTP host, all interfaces receive NTP packets)
Command Modes INTERFACE
Command History
Version 8.3.11.1 Introduced on the Z9000.
Version 8.3.7.0 Introduced on the S4810.
Version 7.6.1.0 Introduced on the S-Series.
Version 7.5.1.0 Introduced on the C-Series.
pre-Version 
6.1.1.0
Introduced on the E-Series.
ntp multicast client
Configure the switch to receive NTP information from the network via multicast.
E-Series, Z-Series, S4810
Syntax
ntp multicast client [multicast-address]
To disable multicast reception, use the no ntp multicast client [multicast-
address] command.
Parameters
multicast-
address
(OPTIONAL) Enter a multicast address. Enter either an IPv4 address in 
dotted decimal format or an IPv6 address in X:X:X:X::X format. If you 
do not enter a multicast address, the address:
1435