DNSDHCP-DHCP Server and remote virtual Lans.

(Last modified: 10Dec2001)

This document (10014759) is provided subject to the disclaimer at the end of this document.

goal

Can the DHCP Server assign addresses to multiple subnets (on one segment) being serviced through a DHCP relay agent?

Can DHCP 3.x service multiple VLANS?

fact

Novell NetWare 5.0

Novell DNS DHCP Services

Formerly TID 2941323

Binding multiple IP addresses to one interface.

fix

With the advent of virtual LAN's and the binding of multiple IP addresses to one interface problems have come up with clients getting a DHCP address when they are on these secondary subnets. A configuration maybe like this. A router has an interface that is configured with 2 logical subnets, a primary and a secondary but this is one physical segment. There are clients on the primary and secondary subnets and the router is configured to do bootp/dhcp forwarding.

When the client sends a DHCPREQUEST to the router it forwards that to the DHCP server with a 'giaddr' being the primary subnet (in this case we need the client to get address from the secondary subnet). The problem is how does the DHCP server know that the client is on the secondary subnet when the 'giaddr' in the packet shows the request coming from the primary subnet?

The 2.x DHCP cannot handle this situation. The 3.x DHCP will be able to handle this. The DHCP server allows an object to be created called a 'SUBNET POOL'. In this subnet pool object will be defined a number of subnets. When a DHCPREQUEST comes into the server through a forwarder it will check the 'giaddr' and determine if a subnet is configured to service that request. If one is not configured or one is configured but all the addresses have been assigned out then the server will look for a subnet pool with that 'giaddr' in it and try to service the client with one of the other subnets in that pool.

See How to Create a Subnet Pool [no longer available] for more information.

document

Document Title:	DNSDHCP-DHCP Server and remote virtual Lans.
Document ID:	10014759
Solution ID:	4.0.30580852.2284524
Creation Date:	20Aug1999
Modified Date:	10Dec2001
Novell Product Class:	Connectivity Products NetWare

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