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When a 3Com S4500 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.
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The NTP server mode, NTP broadcast mode, or NTP multicast mode takes effect only after the
local clock of the 3Com S4500 Ethernet switch has been synchronized.
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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 S4500 Ethernet switch can work in one of the following NTP modes:
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Configuring NTP Server/Client Mode
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Configuring the NTP Symmetric Peer Mode
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Configuring NTP Broadcast Mode
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Configuring NTP Multicast Mode
To protect unused sockets against attacks by malicious users and improve security, 3Com S4500
series Ethernet switches provide the following functions:
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UDP port 123 is opened only when the NTP feature is enabled.
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UDP port 123 is closed as the NTP feature is disabled.
These functions are implemented as follows:
54-6