Dhcp client services, Router option, Parameter request list option – Enterasys Networks Security Router X-PeditionTM User Manual

Page 380: Dhcp client interaction, Secondary address caveats, Dhcp client services -6, Secondary address caveats -6

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DHCP Client Services

15-6 Configuring DHCP

XSR User’s Guide

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.

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.

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-address or client-identifier)
entered first when created.

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.

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