How to set up wired+wireless using isc-dhcpd&bind9 so that IP's are in the same subnet?

Alban Hertroys haramrae at
Thu Aug 7 15:42:51 UTC 2014

Hi all,

I currently have a setup at home where I have a FreeBSD 9-STABLE gateway with both an em0 and an ath0 adapter (and a 3rd adapter to the internet).
Wired devices such as the Mac, the A/V receiver, the playstation and the TV are configured in one subnet (“wired”) with IP-ranges in
Wireless devices such as the iPad and the mobile phone are configured in another subnet (“wireless”) in IP-ranges

That works like a charm, except… Apps on the iPad to control the TV or the playstation _insist_ that both devices are on the same subnet. Apparently they aren’t, as those apps can’t find my wired devices.

I have been trying to fix that, but I can’t seem to wrap my head around how to do that.

* I currently have 2 bind9 zone files: wired.db & wireless.db and their reverse files: wired.rev & wireless.rev. To achieve what those apps seem to want I suppose I need to merge both zone-files into a single zone, such that the domain names are the same between both networks (assuming that domains and zones are equivalent).

* My (isc-)dhcpd.conf currently has 2 subnets. I am under the impression that I need to keep it that way, as either subnet requires its own gateway and DNS server addresses - they are on different interfaces/routes. I’ll probably have to do something with the inet addresses and masks to make both subnets look like a single one from the outside, but how? My attempts so far have mostly caused errors about overlapping ranges from dhcpd or broke networking entirely.

I’ve been trying to merge both subnets under as subnets + That didn’t work, probably because it breaks broadcasts since the “wired" subnet won’t have broadcast address in its range, or if it does, it probably translates to the “wireless” subnet and goes to the wrong gateway/DNS.

I’ve also been trying to find information how to set up bind zone files for C-level domains, as with such a setup my two IP-ranges should fall within the same domain, which should achieve the same thing (provided those apps are willing to accept a C-level domain range, I imagine they might not for security considerations).

I can’t be the first to attempt something like this, but Google seems to disagree. I’d appreciate some help, or better yet, a working similar configuration that I can compare mine against as I’m obviously a bit out of my league here.


Alban Hertroys
If you can't see the forest for the trees,
cut the trees and you'll find there is no forest.

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