From: Doug@hyperspace.vogon.gov   
      
   Carlos E. R. wrote:   
   > On 24/07/2021 22.42, Andrew wrote:   
   >> Carlos E. R. wrote:   
   >>> On 24/07/2021 12.44, Andrew wrote:   
   >>>> One of my computers is refusing to update, zypper says it cannot resolve   
   >>>> download.opensuse.org.  The problem was first seen around 14 hours ago   
   >>>> and an update had succeeded 48 hours before that.   
   >>>> It is the only system I have which uses Network Manager, it is also ipv4   
   >>>> only (hardware reasons) although in that respect it is not the only one.   
   >>>>    Other xxx.opensuse.org sites *are* accessible to it.   
   >>>>   
   >>>> I will have more time to attack this problem tomorrow, this query is   
   >>>> just on the off-chance that someone else has seen this.   
   >>>> My suspicion was name-resolution on the router - I set up DNS over TLS   
   >>>> (DoT) recently with the primary server being dns.quad9.net - but things   
   >>>> still worked for 48 hours after I made that change.   
   >>>>   
   >>>> OpenSUSE 15.3 Leap, fully patched.   
   >>>   
   >>> Sometimes it is not download.opensuse.org which doesn't resolve, but the   
   >>> mirror that you get redirected to. It is not easy to find out.   
   >>>   
   >>> Another typical problem would be trying to use https instead of http.   
   >>>   
   >>>   
   >>> You will have to diagnose. Start with:   
   >>>   
   >>> host -v download.opensuse.org   
   >>>   
   >>> in the problem computer.   
   >>>   
   >>   
   >> Host download.opensuse.org not found: 2(SERVFAIL)   
   >> Received 39 bytes from (an-ipv6-address)#53 in 0 ms   
   >   
   > I said "host -v ..." - you removed the -v.   
   >   
   >>   
   >> This particular system is hooked up seamlessly via a cable to a WLAN   
   >> device which then goes to the router, all this being invisible to the   
   >> PC.  That WLAN forwarder only knows ipv4.   
   >> It looks as though the problem could be the router returning an ipv6   
   >> address, even though the PC "knows" that it should only be using ipv4.   
   >> Other addresses work.   
   >>   
   >> It's late here.  Tomorrow.   
   >>   
   >> Thanks though   
   >   
   >   
      
   The problem is in the modem/router's DNS settings somewhere.   
   After various tests which got me nowhere I made the following changes:   
   - Turned DNS over TLS (DoT) off (no change)   
   - Network Manager -> wicked  (no change)   
   - Added dns-server settings (1.0.0.1 and 1.1.1.1) - BINGO.   
      
   The modem/router is not supposed to be filtering anything.  No parental   
   controls, no restrictions.  Something stinks.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)