Subject: Re: Relayed lease extension

From: Bernie Volz <[email-masked]>
Date: Fri, 28 Apr 2000 17:57:54 -0400

>The PPP user is just using PPP over AAL5 (or over whatever).
>He's not allowed to have DHCP clients asking
>for multiple addresses (that's may be another issue, if
>somebody would want this).
>
>
>                       BigBox
>                    +----------+
>            |-------|DHCP      |            
>DHCPd ------|       |client/   |             
>                    |relay    P|---------PPP
>                    |         P|--------PPP
>                    |         P|
>                    |         d|-----------PPP
>                    +----------+
>

This set-up might be used in other instances where the end-client never
gets an address via DHCP itself (if I recall, PPP sends it in the inital
negotiation to the client and thus the client isn't running DHCP at
all). If the BigBox gets the lease on the address for a shorter time
than the client is connected, it will need to renew the lease and hence
the situation Wim is looking at.

I do think this is a reasonable problem to solve and should be included
on the list of issues for revisions to the DHCP RFC. The simply policy
of sending the reply to the giaddr might be best and it is consistent
with what's done on the initial lease.

Note: In the above case, I'm not sure I'd call the "DHCP thing" on the
"BigBox" a DHCP Relay. It really is more of a DHCP Client on behalf of
the actual client. If it is a classic relay, then as Bernard says, the
client is doing DHCP and thus there is no need for the relay to become
involved in the renewals.

- Bernie