Reservation best practices?

[Allie Hopkins]

Take the router option out of the pool and put into the subnet instead.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Allie M Hopkins
Information Technology Services
Louisiana State University
(225)578-1987


On Wed, Jul 13, 2011 at 11:51 AM, Joshua Beard <josh at hewbert.com> wrote:

>
> On Jul 12, 2011, at 2:53 PM, Joshua Beard wrote:
>
> >
> > On Jul 12, 2011, at 12:17 PM, Joshua Beard wrote:
> >
> >> Greetings,
> >>
> >> This is likely a rookie question, but I thought I'd ask the list.
> >>
> >> The scenario:
> >> We've received many new printers on our network this week, which already
> had hostnames preset to conform to our standards and were setup for DHCP.
>  My plan was to let them get DHCP and then reserve the address for them by
> using the MAC.
> >>
> >> After reading around, it looks like reservations don't work that way in
> ISC DHCP.  My understanding is that the reserved address cannot be in the
> lease pool.  Unfortunately, these printers have already received addresses
> in the pools of their respective subnets.
> >>
> >> Additionally, some of the folks setting them up may have already added
> these printers via their IP addresses to client machines.
> >>
> >> What's recommendations are there to handle this?  I'm thinking I'll have
> to set aside a block of addresses in each subnet that's not in the pool and
> reserve them in that and wait for them to make a new request, then adjust
> any client machines that are talking to them via IP.  Is this my best
> option?  Is there a clean way to do this with ddns in mind?
> >>
> >> Thanks in advance,
> >> Josh
> >
> >
> > Thanks for all the responses.  I ended up just setting aside a range from
> each subnet's non-pooled addresses and designating them for reservations and
> hacking together a couple of scripts to bulk import them into BIND and
> DHCP's configs.
> >
> >
>
> GAH!  I spoke too soon.  They're getting their reservations and talking -
> but only on their subnet.  They aren't getting the router/default gw from
> the DHCP server.  I have "option routers 172.30.xxx.xxx" for each subnet.  I
> tried doing the same on the reservation definition, but no dice.
>
> I hate to do this, and I hope it's not too much to ask, but I'd like to
> post part of my config to get any input.
>
> Thanks,
> Josh
>
>
>
> ddns-update-style interim;
> ignore client-updates;
> ddns-domainname "dsdk12.schoollocal.";
> ddns-rev-domainname "in-addr.arpa.";
>
> key dhcpupdate {
>        algorithm hmac-md5;
>        secret "---secret---";
> }
>
> zone dsdk12.schoollocal. {
>        primary 127.0.0.1;
>        key dhcpupdate;
> }
>
> zone 30.172.in-addr.arpa. {
>        primary 127.0.0.1;
>        key dhcpupdate;
> }
>
> option domain-name "dsdk12.schoollocal";
> option domain-name-servers 172.30.112.121
> option ip-forwarding off;
>
> default-lease-time 7200; # I'll adjust later
> max-lease-time 8000; # I'll adjust later
>
> option time-offset -17000;
> option ntp-servers 172.30.112.126;
>
> authoritative;
> log-facility local7;
>
> include "/etc/dhcp3/dhcpd.reservations.conf";
> include "/etc/dhcp3/printers.reservations.conf";
>
>
>
> Example subnet:
> subnet 172.30.112.0 netmask 255.255.240.0 {
>                authoritative;
>
>                # This is the full range
>                #range 172.30.112.3 172.30.127.254;
>
>                pool {
>                range 172.30.115.1 172.30.127.254;
>                                option subnet-mask
>  255.255.240.0;
>                                option broadcast-address
>  172.30.112.255;
>                                option routers
>  172.30.112.2;
>                }
>
> } # // ITdept
>
>
>
> Example printer reservation:
> host vnbandk3920.dsdk12.schoollocal {
>    hardware ethernet 00:c0:ee:7d:bc:80;
>    fixed-address 172.30.176.243;
> }
>
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>
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