[Dnsmasq-discuss] Behavior change of upstream servers set via DBus

[Matus UHLAR - fantomas]

On 11.11.21 15:12, Jerry Xiao wrote:
>I know this might be a little too long, you can completely discard this
>but DO NOT read part of it and then make such grammarly incorrect and
>baffling replies.
>
>Maybe I did not clearly state what I was doing, I'll be verbose this
>time.
>
>I'd like to:
>Connect to a random wifi or ethernet (you can't hard code its dns
>server, this won't work) with dns poisoning.
>Define a known domain list that is not poisoned.
>Connect directly to the dhcp dns for those domains to minimize impact
>on the local CDN.

which means: point list of known domains to DHCP-configured DNS server


>For those domains that are not in this list, redirect it to another dns
>server.

which means: use different default DNS server.

> EDNS is not that good at preserving local CDNs but it's still
>better than getting bogus results.

I still fail to see how is this diferent from:

1. configuring list of known domains and point them to local server
server=/google.com/192.168.1.1

(192.168.1.1 is the server name provided by dhcp, so you need to build this
everytime dhcp changes)


2. pointing everything else to default DNS server do 1.1.1.1
server=1.1.1.1


>I was using dnsmasq 2.85 to do all of this, until it is upgraded and no
>longer works. I'm not quite sure if it is an unintentional feature on
>the old version 2.85, in option.c there is a piece of clearly
>intentional code to deal with the sharp inside something like
>"server=/#/1.1.1.1"
>
>if (strcmp(arg, "#") == 0)
>  domain = "";
>
>this also sets the SERV_HAS_DOMAIN server flag below.
>I remember seeing the feature being discussed in the mailing list,
>though the thread is not that easy to find.
>
>I spent some more time digging into the code base, only to find out
>that there is no "easy" way to implement this in the new version
>because of the new sorting algorithm used for choosing servers, the
>vastly changed server flags (SERV_HAS_DOMAIN, along with some other
>flags, are removed) and the fact that server flags and query flags are
>already full, idk if the upstream is willing to merge my changes if the
>size of the flags are enarged.
>
>Worst case I just replace dnsmasq with systemd-networkd, but before
>that I'd like to know if there's still other ways to implement this.
>
>Any help is appreciated.
>
>Thanks
>Jerry
>
>On Tue, 2021-11-09 at 17:23 +0100, Matus UHLAR - fantomas via Dnsmasq-
>discuss wrote:
>> On 09.11.21 22:10, Jerry Xiao wrote:
>> > I have 30k+ lines of rules like "server=/somehost.tld/#" in my
>> > config.
>>
>> holy sh...!
>>
>> > What I need is to use the dhcp assigned dns server for those 30k+
>> > domains and forward the others to 1.1.1.1.
>>
>> define 1.1.1.1 as default, so everything will be forwarded to 1.1.1.1
>>
>> forward all those 30k+ domains to DHCP assigned server.
>>
>> server=/somehost.tld/192.168.1.1
>> server=/google.com/192.168.1.1
>>
>> so all those domains will be forwarded there.
>>
>> > This is not possible with your config.
>>
>> it is not possible with _your_ config.
-- 
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