Dhcp Select Global - 3Com 5500-EI PWR Reference Manual

To improve security and avoid malicious attacks to the unused sockets, S5500-EI Ethernet switches
provide the following functions:
UDP ports 67 and 68 used by DHCP are enabled/disabled only when DHCP is enabled/disabled.
The implementation is as follows:
After DHCP is enabled by executing the dhcp enable command, if the DHCP server and DHCP
relay functions are not configured, UDP port 67 and UDP port 68 ports is kept disabled; if the
DHCP server and DHCP relay functions are configured, UDP 67 and UDP 68 ports are enabled.
After DHCP is disabled by executing the undo dhcp enable command, even if the DHCP server
and DHCP relay functions are configured, UDP port 67 and UDP port 68 ports is disabled.
Examples
# Enter system view.
<Sysname> system-view
System View: return to User View with Ctrl+Z.
# Enable DHCP.
[Sysname] dhcp enable

dhcp select global

Syntax
VLAN interface view:
dhcp select global
undo dhcp select
System view:
dhcp select global { interface interface-type interface-number [ to interface-type interface-number ] |
all }
undo dhcp select { interface interface-type interface-number [ to interface-type interface-number ] |
all }
View
System view, VLAN interface view
Parameters
interface interface-type interface-number [ to interface-type interface-number ]: Specifies the
interface(s) to operate in global address pool mode. The interface-type argument specifies an interface
type; the interface-number argument specifies an interface number; the interface interface-type
interface-number [ to interface-type interface-number ] keyword and argument combination specifies
an interface range.
all: Specifies all interfaces to operate in global address pool mode.
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