Ubuntu update to isc-dhcp-server seems to have broken config file processing

bls s bls3427 at outlook.com
Fri Jun 4 14:01:52 UTC 2021

Thanks, Simon for confirming my understanding.

Yes, have backed off to the previous version and it works, so there's a workaround.

I'm off to sort out how to file an actual bug report on Ubuntu in the hope that they revert the change (whatever it is!).


-----Original Message-----
From: dhcp-users <dhcp-users-bounces at lists.isc.org> On Behalf Of Simon Hobson
Sent: Friday, June 4, 2021 5:03 AM
To: Users of ISC DHCP <dhcp-users at lists.isc.org>
Subject: Re: Ubuntu update to isc-dhcp-server seems to have broken config file processing

bls s <bls3427 at outlook.com> wrote:

> I'm using isc-dhcp-server 4.4.1-2 on RasPiOS Buster, and it's working fine with the following subnet declaration:
> subnet netmask {
>     option domain-search "foo.com", "dyn.foo.com";
>     option broadcast-address;
>     allow duplicates;
>     ddns-updates off;
>     pool {
>         ddns-updates on;
>         allow unknown-clients;
>         option domain-name "dyn.foo.com";
>         ddns-rev-domainname "dhcp";
>         default-lease-time 86400;
>         max-lease-time 86400;
>         range;
>     }
> }

That looks fine

> This same subnet config worked on Ubuntu 21.04 a couple of weeks ago, with isc-dhcp-server V4.4.1-2.2-ubuntu6 on it. Today I updated on Ubuntu, got isc-dhcp-server V4.4.1-2.2ubuntu6.1 and now isc-dhcp-server complains about "Can't clone pool group".
> I found that I can put the pool declaration outside of the subnet declaration on Ubuntu, and it works correctly. Unfortunately, doing this on RasPiOS fails!

Having a pool outside of a subnet isn't a valid config. It may appear to work, as do some other config errors, but may cause some really "interesting" issues.

> Am I totally using subnet and pool incorrectly, or is this an incompatible change in isc-dhcp-server? And, is it an intended change coming to mainline isc-dhcp-server or did Ubuntu bork it?

I'd be thinking that there's something changed in the Ubuntu version. Can you roll-back to the earlier version and try it again ?


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