DHCP w/ FHRP and duplicate requests

[Arran Cudbard-Bell]

On 12 Mar 2014, at 11:24, Phil Mayers <p.mayers at IMPERIAL.AC.UK> wrote:

> All,
> 
> I haven't had the chance to try FR DHCP yet, but I ran into a problem with ISC yesterday and I thought I'd mention something worth considering.
> 
> If you have something like VRRP/HSRP for first-hop resilience, both routers will forward the DHCP packet, and you'll get two copies that differ only in giaddr, very close together in time.
> 
> For fixed IPs this isn't usually a problem, but if you're allocating a lease by DB lookup, I guess it would be possible for 2 DISCOVERs to get 2 different OFFERs, particularly if you're threaded.
> 
> I'm wondering if the radius "duplicate packet detection" code could be re-used here?
> 
> It seems like rlm_cache would probably run "too late"?

Why do you think it would be run too late?

Arran Cudbard-Bell <a.cudbardb at freeradius.org>
FreeRADIUS Development Team

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