DHCP "static" assignments

Gregory Sloop gregs at sloop.net
Wed Aug 7 19:01:04 UTC 2013

I've seen this topic hashed out in quite a few threads, namely that
the current version of ISC-DHCPD doesn't handle reservations like the
Microsoft DHCP server.

[And, IIRC, not like older versions of ISC-DHCPD did either - but
perhaps I recall the old days incorrectly.]

In any case, I'm asking for best practices advice, since a number of
searches don't seem to turn up any definitive answer...

There are two basic methods I'm aware of, for handling this:
[Well, methods that prevent any other host from grabbing the
"DHCP-static" IP, when the intended host isn't up when an unintended
one gets to that address in the pool.]

1) omshell/omapi unlimited reservation.
[Complicated, tl;dr - sounds like much hassle. :) ]

2) The way I do it now.
Set aside pools where I set the option
deny unknown-clients;

Then create host entries for the assignments I want.
host somehost {
        hardware ethernet aa:bb:cc:dd:ee:ff;

This works fine, more or less, but can be a pain if I just want to
"reserve" a single address in the middle of a pool I want unknown
clients to use. [i.e. It's easy to make mistakes in the syntax of the
config, among other issues.]

e.g. pool 1-20, reserve 10
pool .. range 1-9 .. allow unknown-clients
pool .. range 10 .. deny unknown-clients
pool .. range 11-20 allow unknown-clients

So, am I holding it wrong, or is there some other method that is
fairly straight-forward that I'm not aware of?
Or, is this really the proper method for doing what I want?


More information about the dhcp-users mailing list