Named issues with T-Mobile 5G for Business

[Marco Moock]

On 06.01.2026 15:25 Philip Prindeville via bind-users wrote:

> And if I modify isc-dhcp to hand out 1.1.1.1 and 1.0.0.1 as name
> servers instead, things don’t work any better, so yeah… looks like a
> packet loss issue.
> 
> Which is weird, because when speediest does manage to run, I
> sometimes see 630/95mbs … other times… 45/19mbs.

Maybe your ISP handles that differently. Try mtr to the speedtest
server and also try UDP speedtests.

Also run speedtests using iperf.

PS: Such a packet loss breaks most communication protocols, so it is
definitely not a BIND issue.

Feel free to try to ping tr.dorfdsl.de, it will reply to ICMP echo
request and ICMP is not blocked.