Re: DHCP and secondaries

[Zuwei liu <[e-mail]>]

On Wed, 15 May 1996, John Miezitis wrote:

> At 18:40 15/05/96 -0400, you wrote:
> >Excerpts from netdev.dhcp-v4: 15-May-96 DHCP and secondaries by "Tim
> >Peiffer"@nts.umn.ed 
> >> Does anyone know of a pointer to a DHCP package that
> >> supports the use of secondary addresses (i.e, multiple
> >> logical subnets on one interface)?
> >
> >The CMU DHCP server will include this feature in the next released
> >version. We're currently using it locally and waiting for other changes
> >to be integrated before releasing the new version; if you want a copy
> >sooner, we might be able to do something.
> 
> How does it support secondaries?  Do you have to maintain a list of
> secondary addresses and the associated primary addresses?
> 

What we did to support secondaries is the following.

1) In bootptab file, to include secondary gateway address explicitly:

.subnet48:\
        :tc=.global:gw=129.74.48.250 129.74.47.250:sm=255.255.255.0:

dhcp-test.net.nd.edu:tc=.subnet48:ht=ethernet:ha=00508C85E9EB:\
                :ip=129.74.48.12:

2) Instead to do check_net(bp->bp_giaddr,hp->iaddr) in dhcp-3.3.7, we put
a patch to check each gateway address related to the host, then send back
bootp/dhcp reply to the secondary gateway. Note: in this example, the bootp
request comes from a primary gateway 129.74.47.250. The modification needs 
to be done in bootp_request(), dhcp_discover(), dhcp_release(). 

Zuwei Liu
Network Engineering, OIT
University of Notre Dame