DHCP failover setup with several relay agents

[Robert Blayzor]

On Sep 22, 2008, at 10:33 AM, Simon Hobson wrote:
> The simple answer is to configure your relay agents properly - ie to  
> send to both servers at the same time. Either add two helper  
> addresses, or use a broadcast address.



Thanks.  I think what Chuck and you have pointed out is to try and use  
directed broadcast.  I'm just doing some searching to see how that's  
going to effect any hosts on the other interfaces/LAN's of where the  
DHCP servers live.  Shouldn't be to bad as long as the ingress  
firewalls "clean up" that type of inbound traffic.

I think directed broadcast seems like the more reliable way to go... I  
think that by configuring two relay agent/helper IP's may cause some  
problems with packet delivery and race conditions over several  
questionable WAN interface.  If using directed broadcast, at least I  
know the packet got to the server LAN ok and that the chance of both  
servers seeing everything is extremely high.

-- 
Robert Blayzor, BOFH
INOC, LLC
rblayzor at inoc.net
http://www.inoc.net/~rblayzor/