3com 5500-ei pwr Instruccion De Instalación

 

2-17 

 

To improve security and avoid malicious attack to the unused sockets, S5500-EI Ethernet switches 

provide the following functions: 

z 

UDP port 67 and UDP port 68 ports used by DHCP are enabled only when DHCP is enabled.  

z 

UDP port 67 and UDP port 68 ports are disabled when DHCP is disabled. 

The corresponding implementation is as follows: 

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After a DHCP interface address pool is created by executing the dhcp select interface command, 

UDP port 67 and UDP port 68 ports used by DHCP are enabled. 

z 

After a DHCP interface address pool is deleted by executing the undo dhcp select interface 

command and all other DHCP functions are disabled, UDP port 67 and UDP port 68 ports used by 

DHCP are disabled accordingly. 

 

IP addresses of an interface address pool can be statically bound to DHCP clients or dynamically 

allocated to DHCP clients.  

Some DHCP clients, such as WWW servers, need fixed IP addresses. This is achieved by binding IP 

addresses to the MAC addresses of these DHCP clients. When such a DHCP client applies for an IP 

address, the DHCP server finds the IP address corresponding to the MAC address of the DHCP client, 

and then assigns the IP address to the DHCP client. 

When some DHCP clients send DHCP-DISCOVER packets to the DHCP server to apply for IP 

addresses, they construct client IDs and add them in the DHCP-DISCOVER packets. The DHCP server 

finds the corresponding IP addresses based on the client IDs and assigns them to the DHCP clients.  

Follow these steps to configure the static IP address allocation mode: 

Enter system view 

— 

Enter interface view 

interface interface-type 
interface-number 

— 

Configure static binding 

dhcp server static-bind ip-address 
ip-address { client-identifier 
client-identifier | mac-address 
mac-address } 

Required 

By default, static 
binding is not 
configured.