request for advice / building dhcpd infraestructure

[Simon Hobson]

Leandro <ingrogger at gmail.com> wrote:

> After I run out of those ips, I can do two thinks:
> a)change the network mask from /24 to /23.
> b)Add a second /24 subnet behind the relay , for example 1.1.2.0/24 and set a second gateway ip 1.1.2.1/24.
> 
> option a) is not good since the broadcast domain at /23 could bring many collisions. (its just my opinion).

I don't think it will make much difference. Don't forget that having two subnets in a shared network won't segregate the broadcast traffic. I think the only reduction would be from inter subnet traffic going via the router rather than using ARP to find the neighbour - but routing the traffic via the router rather than directly will more than outweigh any saving there.

> option b) Could work but, how does relay agent knows witch ip to use for GI-Adrr ?
> Can relay agent send both or more than one ips, on the GI-Addr field so dhcpd can figure out from witch range can serve the ip ?

As already mentioned, as long as the GI-Addr value is within any of the subnets, then the server will work it out from the shared-network.

BTW - I'd suggest a read of "The DHCP Handbook" by Ralph Droms and Ted Lemon, it explains all this and a lot more, and is quite readable.