Pool independent GI Address

Stephan Sanders stephan at sanders.koeln
Sun Dec 14 18:38:15 UTC 2014

Hi Simon,

 14.12.2014 18:25, from Simon Hobson:
>> DHCP relay on remote routers supports only the usage one GI address.
> Well that's implementation specific - it must use "an" address which is within a subnet on the remote network. But if it has more than one, how can it work out which to use ?
Ok. Thats a fact and the verification i can't go this way.

>Why is it not possible to use the same *subnet* for both servers ?

This is a complicated backup situation with 2 separated sites.
Server and VPN GW are located behind a firewall which allows only static
The backward side of the VPN GW (unsecure) propagate their Network
( / to the backbone.
So only the local network from each server site could be used.

>Also, basically why it isn't working is you have lied to the servers
about the network. If they don't know that,,
and are all on the same >physical network (technically,
same broadcast domain) then they won't work. So your config needs to be
: shared-network "foo" { <any shared-network specific options> subnet
> ... subnet ... subnet ... }

>Configure this on both servers, configure the pool(s) (or just
range(s)) you want each server to allocate addresses out of, and it'll
"just work". Remember that you do not have to >have an address pool in a
subnet - it can be empty. The shared-network statement tells the server
that the three subnets are all carried on the same wire - and so devices
may be >using addresses from any of them. When it gets a request with a
GI-Addr in the subnet, it will know it can allocate
addresses from any ranges defined in any of the >three subnets.

I will test this situation to configure the GI addr space also as a
pool. I hope the option 82 will then point the server to use the other
address space.

Best regards

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