DHCP server failover behind relay

[Glenn Satchell]

On Thu, September 6, 2012 4:08 pm, Vadym Abramchuk wrote:
> 2012/9/6 Glenn Satchell <glenn.satchell at uniq.com.au>
>
>> On Thu, September 6, 2012 7:08 am, Vadym Abramchuk wrote:
>> > 2012/9/5 Simon Hobson <dhcp1 at thehobsons.co.uk>
>> >
>> >> Vadym Abramchuk wrote:
>> >>
>> >>  Unfortunally, none of my relay agents can send packets to both
>> servers.
>> >>>
>> >>
>> >> So the proper fix is to get the vendor of the broken relay agent to
>> fix
>> >> it
>> >> ;-)
>> >
>> >
>> > My local supplier said it's not going to happen. At least before
>> Second
>> > Marsian War ends ;-).
>> >
>> Please see this page, for example. Perhaps it is the same software
>> version
>> as your switch?
>>
>> http://sipi.usc.edu/manuals/dell/6024/cli_html/dhcp.htm
>>
>> ip dhcp relay address
>>
>> The ip dhcp relay address global configuration command defines the DHCP
>> servers available for the DHCP relay. To remove a server from the
>> available DHCP servers list, use the no form of this command.
>>
>> Syntax
>>
>> ip dhcp relay address ip-address
>>
>> no dhcp relay address ip-address
>>
>>         ip-address—DHCP server IP address. Up to 8 servers can be
>> defined.
>>
>> HTH.
>>
>>
> Tried this; this way the switch tries to failover DHCP servers in it's own
> meaning.
> That doesn't work as it sends single packet to only one of servers.

That's pretty dumb, but I guess you have to live with it. Saw the other
reply - 40 subnets is too many to provision 40 relay systems, so scratch
that idea.

So that leaves the iptables -j TEE solution. That looks like it would be ok.
 Not ideal, but satisfactory.

My guess is the next network equipment refresh won't include those Dell
switches :)

regards,
-glenn