> On 23. 9. 2025, at 22:21, Petr Špaček <[email protected]> wrote:
> 
> TL;DR their setup is so complicated that resolution from an empty cache is 
> hitting limits designed to prevent misuse/stop attackers from exploiting 
> resolvers.

It's kind of random whether you hit the limits or not though...

$ delv -i +ns mcr.trafficmanager.net -d99 | grep excee
$ delv -i +ns mcr.trafficmanager.net -d99 | grep exce
;; exceeded max queries resolving 'ns4-09.azure-dns.info/AAAA' 
(max-recursion-queries, querycount=50)
;; exceeded max queries resolving 'ns4-09.azure-dns.info/A' 
(max-recursion-queries, querycount=51)
;; exceeded max queries resolving 'ns3-09.azure-dns.org/AAAA' 
(max-recursion-queries, querycount=51, maxqueries=50)
;; exceeded max queries resolving 'ns3-09.azure-dns.org/A' 
(max-recursion-queries, querycount=51, maxqueries=50)
;; exceeded max queries resolving 'ns3-04.azure-dns.org/AAAA' 
(max-recursion-queries, querycount=51, maxqueries=50)
;; exceeded max queries resolving 'ns3-04.azure-dns.org/A' 
(max-recursion-queries, querycount=51, maxqueries=50)
$ delv -i +ns mcr.trafficmanager.net -d99 | grep exce
$ delv -i +ns mcr.trafficmanager.net -d99 | grep exce
$ delv -i +ns mcr.trafficmanager.net -d99 | grep exce
;; exceeded max queries resolving 'ns3-04.azure-dns.org/A' 
(max-recursion-queries, querycount=50)
;; exceeded max queries resolving 'ns3-04.azure-dns.org/AAAA' 
(max-recursion-queries, querycount=51)
$ delv -i +ns mcr.trafficmanager.net -d99 | grep exce
;; exceeded max queries resolving 'ns2-04.azure-dns.net/A' 
(max-recursion-queries, querycount=50)
;; exceeded max queries resolving 'ns1-04.azure-dns.com/AAAA' 
(max-recursion-queries, querycount=51)
;; exceeded max queries resolving 'ns3-09.azure-dns.org/AAAA' 
(max-recursion-queries, querycount=51, maxqueries=50)
;; exceeded max queries resolving 'ns3-09.azure-dns.org/A' 
(max-recursion-queries, querycount=51, maxqueries=50)
;; exceeded max queries resolving 'ns3-04.azure-dns.org/AAAA' 
(max-recursion-queries, querycount=51, maxqueries=50)
;; exceeded max queries resolving 'ns3-04.azure-dns.org/A' 
(max-recursion-queries, querycount=51, maxqueries=50)
$

FTR distributing the DNS among multiple TLDs does not increase resiliency. In 
fact, I believe
using direct in-domain nameservers is the best option instead of this madness. 
I have an old
blogpost on this I might revive and put somewhere again.

Ondrej
--
Ondřej Surý (He/Him)
[email protected]


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