DHCP server failover behind relay

[Vadym Abramchuk]

2012/9/6 Glenn Satchell <glenn.satchell at uniq.com.au>

> On Thu, September 6, 2012 8:06 am, Alex Bligh wrote:
> >
> >
> > --On 6 September 2012 00:08:48 +0300 Vadym Abramchuk <abramm at gmail.com>
> > wrote:
> >
> >> To simplify the things, here's a short cutoff: 10.0.0.70/24 is a
> primary
> >> DHCP server (running at present), 10.0.0.90/24 is secondary one
> >> (actually, it runs in virtual machine). Clients are at different subnet,
> >> 10.8.2.0/23. There's a L3 switch routing between subnets (Dell 6024F in
> >> this case), 10.0.0.1/24 at one side and 10.8.2.1/23 at another side.
> The
> >> switch acts as a DHCP relay.
> >
> > How about run carp or similar on the 2 dhcp servers and use iptables
> > on each server with the -j TEE target (from memory) which will duplicate
> > the packet and send it to the other server. Clearly you'll want dhcp
> > listening on a loopback interface or something with the same IP number
> > on each server, and some proxy arp or similar to get the packet there.
> >
> > --
> > Alex Bligh
>
> How many remote subnets are there? If not too many then you could run an
> ISC dhcrelay process on a system on each network, doesn't have to be the
> gateway.
>
>
I have nearly 40 subnets, over 5000 clients total. I try to keep each
VLAN's edge
far away from network core to avoid MAC address collisions because of full
switch
fdb tables, broadcast storms etc.

--
wbr,
Vadym Abramchuk
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