Dell PowerConnect 7048 - Page 860
What are DHCP Options?, Message Exchange Between DHCP Client and Server
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Figure 31-1. Message Exchange Between DHCP Client and Server DHCPDISCOVER (broadcast) DHCPOFFER (unicast) ` DHCPREQUEST (broadcast) DHCPACK (unicast) DHCP Client DHCP Server (PowerConnect Switch) The DHCP server maintains one or more set of IP addresses the and other configuration information available, by request, to DHCP clients. Each set of information is known as an address pool. After a client leases an IP address from the DHCP server, the server adds an entry to its database. The entry is called a binding. What are DHCP Options? DHCP options are collections of data with type codes that indicate how the options should be used. Options can specify information that is required for the DHCP protocol, IP stack configuration parameters for the client, information allowing the client to rendezvous with DHCP servers, and so on. When a client broadcasts a request for information, the request includes the option codes that correspond to the information the client wants the DHCP server to supply. The Web pages and CLI commands to configure DHCP server settings include many predefined options for the information that is most commonly requested by DHCP clients. For example, DHCP client discover requests typically include options for the IP address (option 50), subnet mask (option 1), default gateway (option 3), and DNS server (option 6). These options are predefined. For options that are not predefined, you can enter the option code and specify the data type along with the data that the switch should include in DHCP offers. RFC2132 specifies many of the DHCP options. Additional options are described in later RFCs. 860 Configuring DHCP Server Settings
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1,206
-
1,207
-
1,208
-
1,209
-
1,210
-
1,211
-
1,212
-
1,213
-
1,214
-
1,215
-
1,216
-
1,217
-
1,218
-
1,219
-
1,220
-
1,221
-
1,222
-
1,223
-
1,224
-
1,225
-
1,226
-
1,227
-
1,228
-
1,229
-
1,230
-
1,231
-
1,232
-
1,233
-
1,234