DHCP "static" assignments

Gregory Sloop gregs at sloop.net
Wed Aug 7 19:43:38 UTC 2013

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

SH> Worth reading !
SH> Not much hassle, and these days I'd suggest it's the better way
SH> to do it. The downside being that there isn't a trivially easy way to manage it.

Ok, perhaps I'll go back and try again - but management is pretty key,
and conf files are more straight-forward, IMO.

>>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

SH> The pool in the middle isn't needed - just leave it out
SH> altogether. The only requirement is that the fixed address sin't in any dynamic range.

So, if there's no pool, but a defined host, the DHCP server will hand
out that IP for any host with the matching MAC address? Really!??!

I was under the impression there had to be a pool for the DHCP server
to hand addresses out of...and that the "deny unknown-clients" just
made sure it didn't hand out IP's in that pool to hosts not already

[IMO, it would still be a lot easier if you just had to put in the host
entry, and then define the pool as 1-20, and it wouldn't assign any
IP's for defined hosts to any other host.

But, I know it just doesn't work that way, and probably for some good
reasons I haven't considered...but as long as I'm wishing! :) ]

SH> As to whether you need to "deny unknown clients", I'm not sure. I
SH> vaguely recall seeing postings to the effect that a client will
SH> continue using it's dynamic address after you've created a fixed
SH> address reservation for it - but I've not got that in my home
SH> setup and that works fine. I don't recall having to do it in the
SH> past either, back when I used dhcp a bit more "in anger" as it were.

SH> There is another method, but that tends to be used more when you
SH> need an assignment based on (for example) opetion 82. That
SH> involves creating a class for each assignment, and a pool to go
SH> with it with "allow members of ...".

I think I know what you're talking about, and it's not very applicable
in the case I envision.


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