Re: Different RPZ behavior for IDN domains between BIND 9.20.23 and 9.20.26

Crist Clark <[email protected]> Sat, 25 Jul 2026 08:35:06 -0700
Newsgroups gmane.network.dns.bind.user
Message-ID <CAAcrURLXQJX9t7AGnUfXMnTe6HXCq+NZ=gL2D17ZguD9zz9jiQ@mail.gmail.com>
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I=E2=80=99d put money on the fact that that domain is fundamentally broken =
with
CNAME at apex as having something to do with it.

The BIND instance having the problem wouldn=E2=80=99t also happen to be dow=
nstream
from another caching resolver?

On Sat, Jul 25, 2026 at 12:33=E2=80=AFAM Ond=C5=99ej Sur=C3=BD <ondrej@isc.=
org> wrote:

> Well, if
> xn--i1bn6adp9emg4dcbcajdeflxp1gua1n7bt10abief.xn--11b7cb3a6a.xn--h2brj9c
> matches bad-domain1.example. then something is definitely wrong.
>
> If you are not willing to share the exact reproducer than there's little
> we can do to help you.
>
> Ondrej
> --
> Ond=C5=99ej Sur=C3=BD (He/Him)
> [email protected]
>
> ADHD brain at work: I sometimes lose track of my inbox. Please feel free
> to send a gentle nudge if you're waiting on a reply!
>
> My working hours and your working hours may be different. Please do not
> feel obligated to reply outside your normal working hours.
>
> > On 25. 7. 2026, at 09:28, Sachchidanand Upadhyay <[email protected]>
> wrote:
> >
> > 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 authoritativ=
e
> 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 9.20.2=
6
> logs the rewrite failure for the same query.
> >
> > Regards,
> > Sachchidanand Upadhyay
> >
> >
> >
> >
> >
> >
> > From: Ond=C5=99ej Sur=C3=BD <[email protected]>
> > To: "Sachchidanand Upadhyay"<[email protected]>
> > Cc: "bind-users"<[email protected]>
> > Date: Fri, 24 Jul 2026 17:12:09 +0530
> > Subject: Re: Different RPZ behavior for IDN domains between BIND 9.20.2=
3
> and 9.20.26
> >
> > What is the rule to trigger this? It is hard to debug without seeing th=
e
> exact ruleset that=E2=80=99s being used.
> >
> > Ondrej
> > --
> > Ond=C5=99ej Sur=C3=BD (He/Him)
> > [email protected]
> >
> > ADHD brain at work: I sometimes lose track of my inbox. Please feel fre=
e
> to send a gentle nudge if you're waiting on a reply!
> >
> > My working hours and your working hours may be different. Please do not
> feel obligated to reply outside your normal working hours.
> >
> > On 24. 7. 2026, at 13:04, Sachchidanand Upadhyay via bind-users <
> [email protected]> wrote:
> >
> > =EF=BB=BFHello,
> >
> > 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 usin=
g
> 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,ba=
dresp: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
> >
> >
> > --
> > Visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe
> from this list.
> >
> >
>
> --
> Visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe
> from this list.
>
>

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<div dir=3D"auto">I=E2=80=99d put money on the fact that that domain is fun=
damentally broken with CNAME at apex as having something to do with it.</di=
v><div dir=3D"auto"><br></div><div dir=3D"auto">The BIND instance having th=
e problem wouldn=E2=80=99t also happen to be downstream from another cachin=
g resolver?</div><div><br><div class=3D"gmail_quote gmail_quote_container">=
<div dir=3D"ltr" class=3D"gmail_attr">On Sat, Jul 25, 2026 at 12:33=E2=80=
=AFAM Ond=C5=99ej Sur=C3=BD &lt;<a href=3D"mailto:[email protected]">ondrej@is=
c.org</a>&gt; wrote:<br></div><blockquote class=3D"gmail_quote" style=3D"ma=
rgin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:=
1ex">Well, if xn--i1bn6adp9emg4dcbcajdeflxp1gua1n7bt10abief.xn--11b7cb3a6a.=
xn--h2brj9c<br>
matches bad-domain1.example. then something is definitely wrong.<br>
<br>
If you are not willing to share the exact reproducer than there&#39;s littl=
e we can do to help you.<br>
<br>
Ondrej<br>
--<br>
Ond=C5=99ej Sur=C3=BD (He/Him)<br>
<a href=3D"mailto:[email protected]" target=3D"_blank">[email protected]</a><br>
<br>
ADHD brain at work: I sometimes lose track of my inbox. Please feel free to=
 send a gentle nudge if you&#39;re waiting on a reply!<br>
<br>
My working hours and your working hours may be different. Please do not fee=
l obligated to reply outside your normal working hours.<br>
<br>
&gt; On 25. 7. 2026, at 09:28, Sachchidanand Upadhyay &lt;<a href=3D"mailto=
:[email protected]" target=3D"_blank">[email protected]</a>&gt; wrote:<br>
&gt; <br>
&gt; Hi Ondrej,<br>
&gt; <br>
&gt; Thank you for your response. <br>
&gt; <br>
&gt; Each listed domain in the RPZ is rewritten via a CNAME to a single pol=
icy domain, and that policy domain has an A record in its authoritative zon=
e.<br>
&gt; <br>
&gt; For example:<br>
&gt; <br>
&gt; bad-domain1.example.=C2=A0 =C2=A0 CNAME=C2=A0 =C2=A0 <a href=3D"http:/=
/policy.example.net" rel=3D"noreferrer" target=3D"_blank">policy.example.ne=
t</a>.<br>
&gt; bad-domain2.example.=C2=A0 =C2=A0 CNAME=C2=A0 =C2=A0 <a href=3D"http:/=
/policy.example.net" rel=3D"noreferrer" target=3D"_blank">policy.example.ne=
t</a>.<br>
&gt; bad-domain3.example.=C2=A0 =C2=A0 CNAME=C2=A0 =C2=A0 <a href=3D"http:/=
/policy.example.net" rel=3D"noreferrer" target=3D"_blank">policy.example.ne=
t</a>.<br>
&gt; bad-domain4.example.=C2=A0 =C2=A0 CNAME=C2=A0 =C2=A0 <a href=3D"http:/=
/policy.example.net" rel=3D"noreferrer" target=3D"_blank">policy.example.ne=
t</a>.<br>
&gt; <br>
&gt; and in the authoritative zone:<br>
&gt; <br>
&gt; <a href=3D"http://policy.example.net" rel=3D"noreferrer" target=3D"_bl=
ank">policy.example.net</a>.=C2=A0 =C2=A0 =C2=A0A=C2=A0 =C2=A0 =C2=A0 =C2=
=A0 &lt;IP address&gt;<br>
&gt; <br>
&gt; <br>
&gt; The same RPZ ruleset works correctly on BIND 9.20.23, while BIND 9.20.=
26 logs the rewrite failure for the same query.<br>
&gt; <br>
&gt; Regards,<br>
&gt; Sachchidanand Upadhyay<br>
&gt; <br>
&gt; <br>
&gt; <br>
&gt; <br>
&gt; <br>
&gt; <br>
&gt; From: Ond=C5=99ej Sur=C3=BD &lt;<a href=3D"mailto:[email protected]" targ=
et=3D"_blank">[email protected]</a>&gt;<br>
&gt; To: &quot;Sachchidanand Upadhyay&quot;&lt;<a href=3D"mailto:supadhyay@=
nkn.in" target=3D"_blank">[email protected]</a>&gt;<br>
&gt; Cc: &quot;bind-users&quot;&lt;<a href=3D"mailto:[email protected]=
rg" target=3D"_blank">[email protected]</a>&gt;<br>
&gt; Date: Fri, 24 Jul 2026 17:12:09 +0530<br>
&gt; Subject: Re: Different RPZ behavior for IDN domains between BIND 9.20.=
23 and 9.20.26<br>
&gt; <br>
&gt; What is the rule to trigger this? It is hard to debug without seeing t=
he exact ruleset that=E2=80=99s being used.<br>
&gt; <br>
&gt; Ondrej<br>
&gt; --<br>
&gt; Ond=C5=99ej Sur=C3=BD (He/Him)<br>
&gt; <a href=3D"mailto:[email protected]" target=3D"_blank">[email protected]</a>=
<br>
&gt; <br>
&gt; ADHD brain at work: I sometimes lose track of my inbox. Please feel fr=
ee to send a gentle nudge if you&#39;re waiting on a reply!<br>
&gt; <br>
&gt; My working hours and your working hours may be different. Please do no=
t feel obligated to reply outside your normal working hours.<br>
&gt; <br>
&gt; On 24. 7. 2026, at 13:04, Sachchidanand Upadhyay via bind-users &lt;<a=
 href=3D"mailto:[email protected]" target=3D"_blank">bind-users@list=
s.isc.org</a>&gt; wrote:<br>
&gt; <br>
&gt; =EF=BB=BFHello, <br>
&gt; <br>
&gt; I am observing different RPZ behavior for an IDN domain after upgradin=
g from BIND 9.20.23 to 9.20.26 and would appreciate any guidance.<br>
&gt; <br>
&gt; Environment:<br>
&gt; <br>
&gt; BIND 9.20.23: Works as expected<br>
&gt; BIND 9.20.26: Fails<br>
&gt; The BIND configuration and RPZ configuration are identical on both ver=
sions.<br>
&gt; <br>
&gt; The queried domain is an IDN. The domain itself is not present in the =
RPZ, yet BIND 9.20.26 logs an &quot;RPZ QNAME rewrite failed&quot; message =
for the query, while the same query is resolved successfully on BIND 9.20.2=
3 using the same configuration. Below are the logs<br>
&gt; <br>
&gt; 24-Jul-2026 15:37:16.288 query-errors: debug 3: client @0x7fd386c93800=
 &lt;client_IP&gt;#41889 (xn--i1bn6adp9emg4dcbcajdeflxp1gua1n7bt10abief.xn-=
-11b7cb3a6a.xn--h2brj9c): view internal: rpz QNAME rewrite xn--i1bn6adp9emg=
4dcbcajdeflxp1gua1n7bt10abief.xn--11b7cb3a6a.xn--h2brj9c stop on qresult in=
 rpz_rewrite(): failure<br>
&gt; 24-Jul-2026 15:37:16.288 query-errors: info: client @0x7fd386c93800 &l=
t;client_IP&gt;#41889 (xn--i1bn6adp9emg4dcbcajdeflxp1gua1n7bt10abief.xn--11=
b7cb3a6a.xn--h2brj9c): view internal: query failed (failure) for xn--i1bn6a=
dp9emg4dcbcajdeflxp1gua1n7bt10abief.xn--11b7cb3a6a.xn--h2brj9c/IN/A at quer=
y.c:7651<br>
&gt; 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--i1bn6adp9emg4dcbcajdeflxp1gua=
1n7bt10abief.xn--11b7cb3a6a.xn--h2brj9c,referral:1,restart:2,qrysent:4,time=
out:0,lame:0,quota:0,neterr:0,badresp:0,adberr:0,findfail:0,valfail:4]<br>
&gt; <br>
&gt; If anyone has encountered this issue before or is aware of a workaroun=
d or solution, I would be grateful for your suggestions.<br>
&gt; <br>
&gt; Regards,<br>
&gt; Sachchidanand Upadhyay<br>
&gt; <br>
&gt; <br>
&gt; -- <br>
&gt; Visit <a href=3D"https://lists.isc.org/mailman/listinfo/bind-users" re=
l=3D"noreferrer" target=3D"_blank">https://lists.isc.org/mailman/listinfo/b=
ind-users</a> to unsubscribe from this list.<br>
&gt; <br>
&gt; <br>
<br>
-- <br>
Visit <a href=3D"https://lists.isc.org/mailman/listinfo/bind-users" rel=3D"=
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sers</a> to unsubscribe from this list.<br>
<br>
</blockquote></div></div>

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