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NTP implementation mode  Configuration on S4200G series switches 
Multicast mode 
z  Configure the local S4200G Ethernet switch to work in 
NTP multicast server mode. In this mode, the local switch 
sends multicast NTP messages through the VLAN 
interface configured on the switch. 
z  Configure the local S4200G Ethernet switch to work in 
NTP multicast client mode. In this mode, the local switch 
receives multicast NTP messages through the VLAN 
interface configured on the switch. 
 
 
z  When a 3Com S4200G Ethernet switch works in server mode or symmetric passive mode, you 
need not to perform related configurations on this switch but do that on the client or the 
symmetric-active peer. 
z  The NTP server mode, NTP broadcast mode, or NTP multicast mode takes effect only after the 
local clock of the 3Com S4200G Ethernet switch has been synchronized. 
z  When symmetric peer mode is configured on two Ethernet switches, to synchronize the clock of the 
two switches, make sure at least one switch’s clock has been synchronized. 
 
NTP Configuration Task List 
Complete the following tasks to configure NTP: 
Task  Remarks 
Configuring NTP Implementation Modes  Required 
Configuring Access Control Right  Optional 
Configuring NTP Authentication  Optional 
Configuring Optional NTP Parameters  Optional 
Displaying NTP Configuration  Optional 
 
Configuring NTP Implementation Modes 
An S4200G Ethernet switch can work in one of the following NTP modes: 
z  Configuring NTP Server/Client Mode 
z  Configuring the NTP Symmetric Peer Mode 
z  Configuring NTP Broadcast Mode 
z  Configuring NTP Multicast Mode 
 
 
To protect unused sockets against attacks by malicious users and improve security, 3Com S4200G 
series Ethernet switches provide the following functions: