How to sync a Linux secondary DHCP server?

[Glenn Satchell]

On Wed, August 1, 2018 11:36 pm, Sandra Schlichting wrote:
>> You could do that as long as there are no dynamic leases (ie: everyone
>> has a fixed-address or similar).
>>
>> You would want to make sure that you didn't have:
>>
>> authoritative;
>>
>> in the config file as that would cause the servers to NAK each other's
>> traffic (I think it still would with fixed-address).
>
> So if I made sure that each dhcp server served dynamic leases in
> different ranges, so no overlap, would it then be a good setup?

Yes you could do that. But I can think of a few problems:

If one server was faster it could have more of the clients getting
addresses from it and fewer from the second server. There is no load
balancing or sharing.

If one server is shutdown or fails, then the clients would eventually
expire their leases, and would get a different address frm the other
server. So persistent connections, such as ssh, web page logns, etc, would
disconenct or need to re-authenticate.

While failover might look difficult, it is actually quite simple to set up
and works very reliably. The failover code has been around for a really
long time, early 2000s, so all the kinks have been well and truly worked
out.

regards,
-glenn