[Bug 1766969] Re: DNS cannot be resolved in Hotel Hotspot

[Mark Daku]

I have encountered this bug as well.

I have raised it with systemd-resolved.
The internal resolver of systemd does not properly search the local dns.  Only fqdn's will resolve.  This is easily mitigated and does not require a whole bunch of enabling or disabling of things.

The DHCP process will almost always provide a valid DNS locally and the
DHCP client in systemd does actually create a valid resolve.conf.  You
just have to point /etc/resolv.conf to it.

At the time of writing the systemd people refuse to accept that this is
a bug. They continue to refer to it as a documentation issue. I honestly
don't believe they are testing it.

# Just making sure I'm out of the / dir
cd /etc
# resolv.conf is a link to ../run/systemd/resolve/stub-resolv.conf Which directs thing to use the local resolved.  So I nuke it.
sudo rm resolve.conf
# Then I go and use the actual resolv.conf that actually works.
sudo ln -s ../run/systemd/resolve/resolv.conf resolv.conf 


The above workaround is good.  It will allow you to take your laptop onto all different types of networks.  It will work correctly.  This is for at least systemd version 237 and above. I haven't checked to see if 236 has the proper file generated or not.

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https://bugs.launchpad.net/bugs/1766969

Title:
  DNS cannot be resolved in Hotel Hotspot

Status in systemd package in Ubuntu:
  Confirmed

Bug description:
  I was asked to create a new bug for this in
  https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1727237 as it
  seems to be a different issue.

  I have installed the nightly image of Kubuntu Bionic from 25th of
  April.

  There systemd is in version 237-3ubuntu10.

  When connecting to the wifi hotspot in my hotel (Quality Hotel
  Augsburg) I cannot open the hotspot landing page that should give me
  access to the WIFI. With Windows and on an Iphone it's working.

  For the following distributions I can confirm it not working:
  Kubuntu 17.10
  Kubuntu 18.04 (nightly image 25th of April 2018)

  The logs were taken on 18.04.

  Workaround:
  sudo systemctl disable systemd-resolved.service
  sudo service systemd-resolved stop
  sudo rm /etc/resolv.conf
  sudo nano /etc/NetworkManager/NetworkManager.conf
    >> add "dns=default" under [main]
  sudo service network-manager restart

  Then I can connect to the WIFI and I see the login page in Firefox.

  To capture some data I did the following:
   - connect to Hotspot
   - enter golem.de

  Case 1: Fresh default Kubuntu install
  With a default Kubuntu install it does not work. I can connect to the WIFI and get IP and DNS from DHCP but I cannot resolve any hostname. When trying  to open the router ip directly in the browser it forwards to hotsplots.de which cannot be resolved.

  Case 2: With aforementioned Workaround
  I connect to the wifi, I open firefox and the login page shows up (if I havent been connected yet. In the capture I already was able to connect to the hotspot which allows immediately to connect to the webpage)

  PS: I'll be in this hotel till Friday 27th if more information are
  required.

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