[Dnsmasq-discuss] Disabling AAAA records for a given domain

Simon Kelley simon at thekelleys.org.uk
Sun Feb 9 20:51:36 GMT 2020


On 07/02/2020 15:13, Abhishek Patti wrote:
> Hi Everyone 
> 
> What is a recommended way to disable "AAAA" records for given domain
> using dnsmasq?
> 
> I have followed solution provided here
>https://discourse.pi-hole.net/t/solved-disable-aaaa-response-for-a-given-domain/13143 but
> i notice dnsmasq still serving AAAA records. 
> 

Is the domain in question a locally-defined one, or something which is
coming from upstream?


Simon.


> Thank you 
> 
> On Thu, Feb 6, 2020 at 4:05 AM
> <dnsmasq-discuss-request at lists.thekelleys.org.uk
> <mailto:dnsmasq-discuss-request at lists.thekelleys.org.uk>> wrote:
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>     Today's Topics:
> 
>        1. Re: [PATCH] DHCPv6 - List or Range reservation for single
>           host (Simon Kelley)
> 
> 
>     ----------------------------------------------------------------------
> 
>     Message: 1
>     Date: Wed, 5 Feb 2020 12:10:50 +0000
>     From: Simon Kelley <simon at thekelleys.org.uk
>     <mailto:simon at thekelleys.org.uk>>
>     To: hjensas at redhat.com <mailto:hjensas at redhat.com>, Tore Anderson
>     <tore at fud.no <mailto:tore at fud.no>>,
>             dnsmasq-discuss at lists.thekelleys.org.uk
>     <mailto:dnsmasq-discuss at lists.thekelleys.org.uk>
>     Subject: Re: [Dnsmasq-discuss] [PATCH] DHCPv6 - List or Range
>             reservation for single host
>     Message-ID: <f3dfbe06-5e4a-3a51-5e4c-d4566861879e at thekelleys.org.uk
>     <mailto:f3dfbe06-5e4a-3a51-5e4c-d4566861879e at thekelleys.org.uk>>
>     Content-Type: text/plain; charset=utf-8
> 
>     On 04/02/2020 14:24, Harald Jens?s wrote:
>     > On Tue, 2020-02-04 at 00:06 +0000, Simon Kelley wrote:
>     >> I went though this carefully, and decided that replacing the address
>     >> in
>     >> the dhcp-host with the next free one, but otherwise treating things
>     >> the
>     >> same might not work well. For instance, there are places where the
>     >> question is asked "is this address reserved in any dhcp-host?" and
>     >> clearly that needs to be modified to answer "yes" to any of the
>     >> addresses when there is more than one.
>     >>
>     >
>     > I thought this was only the case for IPv4? I.e I did'nt see that check
>     > for IPv6 and tought it deliberately allowed having the same IP address
>     > in different host-entries? (Fir laptop with wired/wireless interface
>     > get's the same ip and such use cases?) Since it's checking for an
>     > existing lease, it does'nt lease the same address to both hosts
>     > simultaneously.
>     >
> 
> 
>     > I can with this patch put the following configuration, and dnsmasq
>     > starts and serves addresses to the two different hosts from the same
>     > address set.
>     >
>     > dhcp-host=52:54:00:bc:c3:fd,[fd12:3456:789a:1::aa04/126],host2
>     > dhcp-host=52:54:00:3f:5c:c0,[fd12:3456:789a:1::aa04/126],host1
>     >
>     > With the git master; as well as older version 2.76 (the one in
>     CentOS);
>     > I also tested this configuration where two hosts share the same IP:
>     > dhcp-host=52:54:00:bc:c3:fd,[fd12:3456:789a:1::aa04],host2
>     > dhcp-host=52:54:00:3f:5c:c0,[fd12:3456:789a:1::aa04],host1
>     >
>     > The configuration loads without error, and the first host to capture
>     > the reservation gets the lease. The second one get "no addresses
>     > available".
>     >
>     > Because of the above existing behaviour, I came to the conclusion that
>     > implementing any check to verify each address in the arbitrary address
>     > list wasn't necessary. I may have missed something?
>     >
> 
>     There are a couple of cases, which are covered by calls to
>     config_implies() in the patch.
> 
>     1) A host asks for an address which is static-only, either because the
>     network is declared for static addresses, or the address is outside the
>     range declared for dynamicic allocation. The semantics change to
>     allowing the address in --dhcp-host to any of the addresses in
>     --dhcp-host.
> 
>     2) Something like
> 
>     dhcp-host=<address>,<lease_length>
> 
>     is valid, and has to override the default lease length for the whole set
>     of addresses now.
> 
>     >> I ended with a different implementation of the same thing, with the
>     >> exception that I only supported a prefix range of addresses, and not
>     >> an
>     >> arbitrary list. That makes the internal representation much simpler.
>     >>
>     >> A quick test passes fine, but Harald you clearly have a better test
>     >> harness. Please could you put this through its paces, and see if it
>     >> does
>     >> what you need.
>     >>
>     >
>     > I ran some tests with your patch, and I did not run into any issues
>     > with the prefix support.
>     >
>     > Unfortunately, for my use-case in openstack the arbitrary list is the
>     > useful option between the two. There is currently no way in openstack
>     > networking api to ask the ip-address management to allocate a set of
>     > consecutive addresses. Adding support for the prefix approach is a
>     > major change to api, object model's, database schema etc.
>     >
>     > Any chance we can add the arbitrary list back in?
> 
> 
>     Yes, no problem doing that. I didn't appreciate it was necessary. New
>     commit soon, and I'll also look at the tagging one.
> 
> 
> 
>     Cheers,
> 
>     Simon.
> 
>     Or revert to my
>     > initial approach allowing multiple host-entries with different
>     > addresses? With the tag filtering support added for dhcp-hosts the
>     > issue of ordering of entries in configuration file is somewhat
>     relaxed,
>     > as in; it's possible to control via tag's and filters.
>     >
>     >
>     >
>     > Cheers
>     > Harald
>     >
>     >
>     >
> 
> 
> 
> 
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>     End of Dnsmasq-discuss Digest, Vol 177, Issue 5
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> 
> 
> -- 
> abhishek
> 
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