Different RPZ behavior for IDN domains between BIND 9.20.23 and 9.20.26

[Sachchidanand Upadhyay]

Hi Ondrej,



Thank you for your response. 



Each listed domain in the RPZ is rewritten via a CNAME to a single policy domain, and that policy domain has an A record in its authoritative zone.



For example:



bad-domain1.example.    CNAME    policy.example.net.

bad-domain2.example.    CNAME    policy.example.net.

bad-domain3.example.    CNAME    policy.example.net.

bad-domain4.example.    CNAME    policy.example.net.



and in the authoritative zone:



policy.example.net.     A        <IP address>





The same RPZ ruleset works correctly on BIND 9.20.23, while BIND 9.20.26 logs the rewrite failure for the same query.



Regards,

Sachchidanand Upadhyay












From: Ondřej Surý <ondrej at isc.org>
To: "Sachchidanand Upadhyay"<supadhyay at nkn.in>
Cc: "bind-users"<bind-users at lists.isc.org>
Date: Fri, 24 Jul 2026 17:12:09 +0530
Subject: Re: Different RPZ behavior for IDN domains between BIND 9.20.23 and 9.20.26



What is the rule to trigger this? It is hard to debug without seeing the exact ruleset that’s being used.

Ondrej
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On 24. 7. 2026, at 13:04, Sachchidanand Upadhyay via bind-users < mailto:bind-users at lists.isc.org > wrote:



Hello, 



I am observing different RPZ behavior for an IDN domain after upgrading from BIND 9.20.23 to 9.20.26 and would appreciate any guidance.



Environment:



BIND 9.20.23: Works as expected

BIND 9.20.26: Fails

The BIND configuration and RPZ configuration are identical on both versions.



The queried domain is an IDN. The domain itself is not present in the RPZ, yet BIND 9.20.26 logs an "RPZ QNAME rewrite failed" message for the query, while the same query is resolved successfully on BIND 9.20.23 using the same configuration. Below are the logs



24-Jul-2026 15:37:16.288 query-errors: debug 3: client @0x7fd386c93800 <client_IP>#41889 (xn--i1bn6adp9emg4dcbcajdeflxp1gua1n7bt10abief.xn--11b7cb3a6a.xn--h2brj9c): view internal: rpz QNAME rewrite xn--i1bn6adp9emg4dcbcajdeflxp1gua1n7bt10abief.xn--11b7cb3a6a.xn--h2brj9c stop on qresult in rpz_rewrite(): failure

24-Jul-2026 15:37:16.288 query-errors: info: client @0x7fd386c93800 <client_IP>#41889 (xn--i1bn6adp9emg4dcbcajdeflxp1gua1n7bt10abief.xn--11b7cb3a6a.xn--h2brj9c): view internal: query failed (failure) for xn--i1bn6adp9emg4dcbcajdeflxp1gua1n7bt10abief.xn--11b7cb3a6a.xn--h2brj9c/IN/A at query.c:7651

24-Jul-2026 15:37:16.288 query-errors: debug 4: fetch completed for xn--i1bn6adp9emg4dcbcajdeflxp1gua1n7bt10abief.xn--11b7cb3a6a.xn--h2brj9c/A in 0.042000: failure/deadlock found [domain:xn--i1bn6adp9emg4dcbcajdeflxp1gua1n7bt10abief.xn--11b7cb3a6a.xn--h2brj9c,referral:1,restart:2,qrysent:4,timeout:0,lame:0,quota:0,neterr:0,badresp:0,adberr:0,findfail:0,valfail:4]



If anyone has encountered this issue before or is aware of a workaround or solution, I would be grateful for your suggestions.



Regards,

Sachchidanand Upadhyay





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