Enterasys Networks X-PeditionTM Dhcp Client Services, Router Option, Dhcp Client Interaction

DHCP Client Services

Note: Manual bindings can be added by performing steps 2 and 3 in any order. But, when deleting a binding, enter the no form of the command (host, hardware-addressor client-identifier) entered first when created.

4.Optionally, specify the client name using any standard ASCII character. Enter client-name <name>.

The client name should not include the domain name. For example, the name acme should not be specified as acme.enterasys.com.

DHCP Client Services

Router Option

The XSR’s DHCP Client implementation supports Router Option (DHCP Option 3). When one or more host IP addresses exist in the Router Option, the first host IP address will be used as the default IP route. The following sample debug level logging message is generated:

XSR-1200 DHCP: Set IPA (192.168.70.102/24) and Default Gateway (192.168.70.1) on interface FastEthernet0

Such a route with a cost of 254 is entered in the routing table and can be displayed by the show ip route command as follows:

XSR-1200#show ip route

Codes: C-connected, S-static, R-RIP, B-BGP, O-OSPF, IA-OSPF interarea

		N1	- OSPF	NSSA external	type 1, N2		- OSPF NSSA external type	2
*		E1	- 0SPF external type		1,	E2 - 0SPF external type 2, H-DHCP		default
	- candidate default, D - default route originated from default net
*	C	192.168.70.0/24			[	0/0001]	directly connected, FastEthernet0
	H	0.0.0.0/0			[254/0001]		via 192.168.70.1, FastEthernet0

This route will be reset and deleted from the routing table if this particular interface is down or the DHCP lease expires and can not be renewed. A logging message will be generated as follows:

XSR-1200#<191>Jan 2 00:24:54 XSR-1200 DHCP: Zero IPA and Clear Default Gateway (192.168.70.1) on interface FastEthernet0

Parameter Request List Option

DHCP Option 55 is used by the DHCP Client to request values for specific configuration parameters. Currently, this list is not configurable; the default value is the Subnet Mask.

Note: Although Routers, Domain Name, and Hostname values are typically included in Option 55, these are not used by this client unless the client is part of RAI.

DHCP Client Interaction

Secondary Address Caveats

DHCP negotiation and secondary addresses are mutually exclusive on the XSR. An interface configured with secondary addresses cannot be switched to DHCP negotiation and an interface configured for DHCP negotiation will reject any secondary address commands.

15-6 Configuring DHCP XSR User’s Guide