[Bug 1827640] [NEW] DHCP provided domain-name not respected while performing name lookups during install

[Launchpad Bug Tracker]

You have been subscribed to a public bug:

Ubuntu 18.04 is ignoring dhcp provided domain-name for name lookups
during install.  I suspect that this is also a problem for 19.04 but
have not verified the behavior on that build as of yet, but I have also
checked the release notes and cannot find anything pertaining to a fix
either.

This issue is being spawned from an ask-ubuntu question as I went there first for help.  I am filing a bug since I am now satisfied that this has enough information and criteria to fit the description of a confirmed bug.
The question this bug is being cloned from can be found at:
https://askubuntu.com/questions/1139883/18-04-ignoring-dhcp-provided-domain-name-for-name-lookups-during-install

I'm not sure what package this pertains to exactly as I am not sure
where the problem is yet since correcting the resolve.conf file in the
installer allows the install to continue as it should.  However the
issue could be in either dhclient it's self or a processed script which
is triggered on each new dhcp lease. Either way, it's a pretty serious
issue for anyone who has to use local network resources during an
install and I hypothesize that this should be a simple fix that should
help local installs a great deal.

I could copy the images into the bug, but I'm hoping that isn't needed.
There are a lot of images associated with this bug report since it deals
with the installer.  Those screen shots can be found on the attached
askubuntu.com question.

 I ran into the problem while attempting to get a preconfigure file to perform an automated installation of ubuntu. See the following error:
https://i.stack.imgur.com/Ns4qC.png

The preconfigure file is passed in through the kernel parameters in an
ipxe script like so:

    set theKernelParams auto=true fb=false  interface=auto
priority=critical url=ipxe/ubuntuks.conf

However, this results in an error explaining that we cannot reach the
server "ipxe". This is obviously not true from any machine in the lab
and even not true from any other operating system that I use ipxe to
install.

Further investigation and looking at the console, it would appear that ubuntu is not respecting the dhcp provided domain-name when performing name lookups.  This can be seen in the resolve.conf file and the lease made by dhclient.  After returning an address from dhcp, dhclient should update the resolve.conf file to allow lookup of names that are not using the FQDN.
screenshot:
https://i.stack.imgur.com/rj68V.png

After correcting the resolve.conf:
https://i.stack.imgur.com/cCyzD.png

Proof that ping works with short names after fixing the resolve.conf:

https://i.stack.imgur.com/JPlkp.png

After making the change to the resolve.conf file.. Setup continues with
the preconfigure file like nothing ever happended..

Note: after install resolve.conf shows the following.
https://i.stack.imgur.com/Sz8RL.png

** Affects: casper (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: bot-comment
-- 
DHCP provided domain-name not respected while performing name lookups during install
https://bugs.launchpad.net/bugs/1827640
You received this bug notification because you are a member of Ubuntu Foundations Bugs, which is subscribed to casper in Ubuntu.