[dns-operations] geo9/geo10.t-mobile.com Returning NXDOMAIN for WiFi Calling

[Richard Laager]

FWIW, we have `qname-minimization disabled;` in our config.

Using RPZ in BIND seems to make it do things differently, causing it to 
surface problems like this more often than it would without RPZ. See 
this comment about a similar issue: 
https://gitlab.isc.org/isc-projects/bind9/-/issues/4787#note_470454

On 2025-11-19 00:49, Crist Clark wrote:
> QNAME minimization. Their non-compliant load balancers pretending to 
> be authoritative servers give responses that break QNAME minimization.
>
>
> On Tue, Nov 18, 2025 at 8:06 PM Richard Laager via dns-operations 
> <dns-operations at dns-oarc.net> wrote:
>
>
>
>
>     ---------- Forwarded message ----------
>     From: Richard Laager <rlaager at wiktel.com>
>     To: dns-operations at lists.dns-oarc.net
>     Cc:
>     Bcc:
>     Date: Tue, 18 Nov 2025 21:55:06 -0600
>     Subject: geo9/geo10.t-mobile.com <http://geo10.t-mobile.com>
>     Returning NXDOMAIN for WiFi Calling
>
>     Anyone have a good contact for T-Mobile authoritative DNS? I've
>     had no response from dnsadmin at t-mobile.com.
>
>     My customers are reporting that T-Mobile WiFi calling (sometimes)
>     does not work on our Internet service. This appears to be due to
>     DNS resolution failures.
>
>     The cause of the failures seems to be that geo9.t-mobile.com
>     <http://geo9.t-mobile.com> and geo10.t-mobile.com
>     <http://geo10.t-mobile.com> incorrectly return NXDOMAIN when
>     queried for NS records for
>     epdg.epc.geo.mnc260.mcc310.pub.3gppnetwork.org
>     <http://epdg.epc.geo.mnc260.mcc310.pub.3gppnetwork.org> and
>     epc.geo.mnc260.mcc310.pub.3gppnetwork.org
>     <http://epc.geo.mnc260.mcc310.pub.3gppnetwork.org>. Note that they
>     correctly return an answer when queried for A records. See also:
>     https://dnsviz.net/d/epdg.epc.mnc260.mcc310.pub.3gppnetwork.org/dnssec/
>
>     -- 
>     Richard
>
>
>
>
>     ---------- Forwarded message ----------
>     From: Richard Laager via dns-operations <dns-operations at dns-oarc.net>
>     To: dns-operations at lists.dns-oarc.net
>     Cc:
>     Bcc:
>     Date: Tue, 18 Nov 2025 21:55:06 -0600
>     Subject: [dns-operations] geo9/geo10.t-mobile.com
>     <http://geo10.t-mobile.com> Returning NXDOMAIN for WiFi Calling
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>

-- 
Richard
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